Protein Sequence Analysis Research Articles

Using bioinformatic protein sequence similarity to investigate if SARS CoV-2 infection could cause an ocular autoimmune inflammatory reactions?

Although severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) infection have emerged globally, findings related to ocular involvement and reported cases are quite limited. Immune reactions against viral infections are closely related to viral and host proteins sequence similarity. Molecular Mimicry has been described for many different viruses; sequence similarities of viral and human tissue proteins may trigger autoimmune reactions after viral infections due to similarities between viral and human structures. With this study, we aimed to investigate the protein sequence similarity of SARS CoV-2 with retinal proteins and retinal pigment epithelium (RPE) surface proteins. Retinal proteins involved in autoimmune retinopathy and retinal pigment epithelium surface transport proteins were analyzed in order to infer their structural similarity to surface glycoprotein (S), nucleocapsid phosphoprotein (N), membrane glycoprotein (M), envelope protein (E), ORF1ab polyprotein (orf1ab) proteins of SARS CoV-2. Protein similarity comparisons, 3D protein structure prediction, T cell epitopes-MHC binding prediction, B cell epitopes-MHC binding prediction and the evaluation of the antigenicity of peptides assessments were performed. The protein sequence analysis was made using the Pairwise Sequence Alignment and the LALIGN program. 3D protein structure estimates were made using Swiss Model with default settings and analyzed with TM-align web server. T-cell epitope identification was performed using the Immune Epitope Database and Analysis (IEDB) resource Tepitool. B cell epitopes based on sequence characteristics of the antigen was performed using amino acid scales and HMMs with the BepiPred 2.0 web server. The predicted peptides/epitopes in terms of antigenicity were examined using the default settings with the VaxiJen v2.0 server. Analyses showed that, there is a meaningful similarities between 6 retinal pigment epithelium surface transport proteins (MRP-4, MRP-5, RFC1, SNAT7, TAUT and MATE) and the SARS CoV-2 E protein. Immunoreactive epitopic sites of these proteins which are similar to protein E epitope can create an immune stimulation on T cytotoxic and T helper cells and 6 of these 9 epitopic sites are also vaxiJen. These result imply that autoimmune cross-reaction is likely between the studied RPE proteins and SARS CoV-2 E protein. The structure of SARS CoV-2, its proteins and immunologic reactions against these proteins remain largely unknown. Understanding the structure of SARS CoV-2 proteins and demonstration of similarity with human proteins are crucial to predict an autoimmune response associated with immunity against host proteins and its clinical manifestations as well as possible adverse effects of vaccination.

Interaction of eukaryotic proliferating cell nuclear antigen (PCNA) with the replication-associated protein (Rep) of cotton leaf curl Multan virus and pedilanthus leaf curl virus.

The replication-associated (Rep) proteins of pathogenic begomoviruses, including cotton leaf curl Multan virus (CLCuMuV) and pedilanthus leaf curl virus (PeLCV), interact with the DNA replication machinery of their eukaryotic hosts. The analysis of Rep protein sequences showed that there is 13-28% sequence variation among CLCuMuV and PeLCV isolates, with phylogenetic clusters that can separated at least in part based on the country of origin of the respective viruses. To identify specific host factors involved in the virus replication cycle, we conducted yeast two-hybrid assays to detect possible interactions between the CLCuMuV and PeLCV Rep proteins and 30 protein components of the Saccharomyces cerevisiae DNA replication machinery. This showed that the proliferating cell nuclear antigen (PCNA) protein of S. cerevisiae interacts with Rep proteins from both CLCuMuV and PeLCV. We used the yeast PCNA sequence in BLAST comparisons to identify two PCNA orthologs each in Gossypium hirsutum (cotton), Arabidopsis thaliana (Arabidopsis), and Nicotiana benthamiana (tobacco). Sequence comparisons showed 38-40% identity between the yeast and plant PCNA proteins, and > 91% identity among the plant PCNA proteins, which clustered together in one phylogenetic group. The expression of the six plant PCNA proteins in the yeast two-hybrid system confirmed interactions with the CLCuMuV and PeLCV Rep proteins. Our results demonstrate that the interaction of begomovirus Rep proteins with eukaryotic PCNA proteins is strongly conserved, despite significant evolutionary variation in the protein sequences of both of the interacting partners.

ExBWS: Extended Bioinformatics Web Services for Sequence Analyses

The extended bioinformatics web services (ExBWS) represent a significant extension of the published EBWS PHP-based server providing useful tools for analyses of DNA, RNA, and protein sequences. Six...

Antibiotic Resistance, Virulence Factors and Phylogenetic Analysis of Efflux Proteins of Coagulase Negative <i>Staphylococcus</i> Isolates from Sewage Samples

Multidrug-resistant pathogens are now emergent worldwide and pose a serious threat to disease prevention and treatment. The World Health Organization declared anti-microbial resistance as a major peril to human beings. Staphylococcus is part of the normal microbiome of humans and are responsible for opportunistic infections. Like S. aureus, Coagulase-negative staphylococcus are also clinically important as the causal agents of severe diseases, nosocomial infections, catheter-associated infection, bacteremia, septicemia. Methicillin resistant Staphylococci species are widely known and methicillin resistant CoNS, known as MR-CoNS, have been found to carry the mecA gene. Various virulence factors help these organisms in their pathogenicity and antibiotic-resistance is aided by the presence of efflux pumps. In our study, we have isolated 45 isolates from sewage water which were tentatively identified as CoNS based on biochemical characteristics. Then virulence and antibiotics susceptibility patterns were screened by standard protocols. Multiple drug resistant CoNS were found in our study and in silico analysis of an annotated protein sequence of the efflux pump SepA of Pseudomonas putida was carried out. Sequence analysis of the efflux protein gene revealed that it is phylogenetically related to the AcrA of Staphylococcus sp. and a RND transporter of Vibrio sp. The widespread presence of MR-CoNS is a cause for serious concern as sewage treatment plants are reservoirs for the spread of antibiotic resistance.

ExBWS: extended bioinformatics web services for sequence analyses

The extended bioinformatics web services (ExBWS) represent a significant extension of the published EBWS PHP-based server providing useful tools for analyses of DNA, RNA, and protein sequences. Six new web-based applets are freely available via the ExBWS to the user. They include a DNA/RNA translator, an AminoCODE transformer, a virtual PCR analyser, a protein hydropathy plotter, protein reverse translator, and a Eukaryotic ORF finder. Each applet includes some novel feature. The AminoCODE transformer takes a protein sequence from one letter code to three and vice versa, the virtual PCR analyser generates fragments with or without overhangs, the protein hydropathy plotter makes hydropathy plots of 10 frames of the input sequence, the reverse translator converts proteins to DNA according to the highest codons bias present in the selected organism. The Eukaryotic ORF finder searches for introns in the query sequence and translates ORFs of the processed sequence into proteins. All programs are freely available at http://penchovsky.atwebpages.com/applications.php.

Genome wide identification and expression pattern analysis of the GRAS family in quinoa.

GRAS, a key transcription factor in plant growth and development, has not yet been reported in quinoa. Therefore, this study used the latest quinoa genomic data to identify and analyse GRAS genes in quinoa: 52 GRAS genes were identified in quinoa, these being unevenly distributed on 19 chromosomes. Fragment duplication and tandem duplication events were the main reasons for the expansion of the GRAS gene family in quinoa. Protein sequence analysis showed that there were some differences in amino acid numbers and isoelectric points amongst different subfamilies, and the main secondary structures were α-helix and random coil. The CqGRAS gene was divided into 14 subfamilies based on results from phylogenetic analysis. The genes located in the same subfamily had similar gene structures, conserved motifs, and three-level models. Promoter region analysis showed that the GRAS family genes contained multiple homeostasis elements that responded to hormones and adversity. GO enrichment indicated that CqGRAS genes were involved in biological processes, cell components, and molecular functions. By analysing the expression of CqGRAS genes in different tissues and different treatments, it was found that GRAS genes had obvious differential expression in different tissues and stress, which indicates that GRAS genes had tissue or organ expression specificity and thus might play an important role in response to stress. These results laid a foundation for further functional research on the GRAS gene family in quinoa.

RNA Dependent RNA Polymerases of Severe Acute Respiratory Syndrome-Related Coronaviruses- An Insight into their Active Sites and Mechanism of Action

Aim: To analyze the RNA-dependent RNA polymerases (RdRps) of Severe Acute Respiratory Syndrome (SARS)-related coronaviruses (CoVs) to find out the conserved motifs, metal binding sites and catalytic amino acids and propose a plausible mechanism of action for these enzymes, using SARS-CoV-2 RdRp as a model enzyme.
 Study Design: Bioinformatics, Biochemical, Site-directed mutagenesis (SDM), X-ray crystallographic and cryo-Electron microscopic (cryo-EM) data were analyzed.
 Methodology: Bioinformatics, Biochemical, Site-directed mutagenesis, X-ray crystallographic and cryo-EM data of these enzymes from RNA viral pathogens were analyzed. The advanced version of Clustal Omega was used for protein sequence analysis of the RdRps.
 Results: Multiple sequence alignment (MSA) of RdRps from different SARS-related CoVs show a large number of highly conserved motifs among them. Though the RdRp from the Middle Eastern Respiratory syndrome (MERS)-CoV differed in many conserved regions yet the active site regions are completely conserved. Possible catalytic regions consist of an absolutely conserved amino acid K, as in single subunit (SSU) RNA polymerases and most of the DNA dependent DNA polymerases (DdDps). The invariant ‘gatekeeper/DNA template binding’ YG pair that was reported in all SSU DNA dependent RNA polymerases (DdRps), prokaryotic multi-subunit (MSU) DdRps and DdDps is also highly conserved in the RdRps of SARS-CoVs. The universal metal binding motif –GDD- and an additional motif–SDD- are also found in all SARS-CoV RdRps. In stark contrast, the (–) strand RNA viral pathogens like Ebola, rabies, etc. use –GDN- rather than –GDD- for catalytic metal binding. An invariant YA pair (instead of an YG pair) is found in the primases of the SARS-CoVs. The SARS-CoVs RdRps and primases exhibit very similar active site and catalytic regions with almost same distance conservations between the template binding YG/YA pair and the catalytic K. In SARS-CoV RdRps an invariant R is placed at -5 which is shown to play a role in nucleoside triphosphate (NTP) selection and is in close agreement with SSU DdRps (viral family) and DdDps. In primases no such invariant R/K/H is found very close to the catalytic K in the downstream region, as found in RdRp and Nidovirus RdRp-Associated Nucleotidyltransferase (NiRAN) domains. An invariant YA pair is placed in the NiRAN domain instead of an YG pair, and an invariant H is placed at -5 position. Moreover, the Zn binding motif with the completely conserved Cs and a few DxD/DxxD type metal binding motifs are found in the RdRps and NiRAN domain. However, the primases contained only the DXD type metal binding motifs.
 Conclusions: The SARS and SARS-related CoV RdRps are very similar as large peptide regions are highly conserved among them. The closer identity between the RdRps of palm civet-CoV and SARS-CoV (CoV-1) suggest their possible link as found between their spike proteins also. The invariant YG and KL pairs may play a role in template binding and catalysis in SARS-CoV RdRps as reported in DdDps. An additional invariant –YAN- motif found in SARS-CoV RdRps may play a crucial role in nucleotide discrimination.

Sequence Comparison Without Alignment: The SpaM Approaches.

Sequence alignment is at the heart of DNA and protein sequence analysis. For the data volumes that are nowadays produced by massively parallel sequencing technologies, however, pairwise and multiple alignment methods are often too slow. Therefore, fast alignment-free approaches to sequence comparison have become popular in recent years. Most of these approaches are based on word frequencies, for words of a fixed length, or on word-matching statistics. Other approaches are using the length of maximal word matches. While these methods are very fast, most of them rely on ad hoc measures of sequences similarity or dissimilarity that are hard to interpret. In this chapter, I describe a number of alignment-free methods that we developed in recent years. Our approaches are based on spaced-word matches ("SpaM"), i.e. on inexact word matches, that are allowed to contain mismatches at certain pre-defined positions. Unlike most previous alignment-free approaches, our approaches are able to accurately estimate phylogenetic distances between DNA or protein sequences using a stochastic model of molecular evolution.

Uncovering chemical signatures of salinity gradients through compositional analysis of protein sequences

Abstract. Prediction of the direction of change of a system under specified environmental conditions is one reason for the widespread utility of thermodynamic models in geochemistry. However, thermodynamic influences on the chemical compositions of proteins in nature have remained enigmatic despite much work that demonstrates the impact of environmental conditions on amino acid frequencies. Here, we present evidence that the dehydrating effect of salinity is detectable as chemical differences in protein sequences inferred from (1) metagenomes and metatranscriptomes in regional salinity gradients and (2) differential gene and protein expression in microbial cells under hyperosmotic stress. The stoichiometric hydration state (nH2O), derived from the number of water molecules in theoretical reactions to form proteins from a particular set of basis species (glutamine, glutamic acid, cysteine, O2, H2O), decreases along salinity gradients, including the Baltic Sea and Amazon River and ocean plume, and decreases in particle-associated compared to free-living fractions. However, the proposed metric does not respond as expected for hypersaline environments. Analysis of data compiled for hyperosmotic stress experiments under controlled laboratory conditions shows that differentially expressed proteins are on average shifted toward lower nH2O. Notably, the dehydration effect is stronger for most organic solutes compared to NaCl. This new method of compositional analysis can be used to identify possible thermodynamic effects in the distribution of proteins along chemical gradients at a range of scales from microbial mats to oceans.

Structure and regulation of the NK-lysin (1–4) and NK-lysin like (a and b) antimicrobial genes in rainbow trout (Oncorhynchus mykiss)

Nk-lysin (Nkl), an antimicrobial peptide (AMP) product of natural killer cells and cytotoxic T cells in mammals, has recently been characterized in a number of finfish species. In this study, we identified six genes with sequence homology to Nkl and characterized their patterns of mRNA expression and abundances in rainbow trout (Oncorhynchus mykiss). The cDNA sequences for the six Nkls encoded precursor peptides of 128–133 aa in length, and mature peptides of 109–111 aa in length. Genomic DNA of the nkl1-4 genes consisted of five exons and four introns, whereas the nkl-like a &b genes consisted of four exons and three introns. Chromosomal locations of these peptides show that nkl1 was located on chromosome arm 25q, whereas the other five nkl genes were clustered on chromosome arm 19q. Phylogenetic analysis revealed a conserved structure of Nkls among the teleosts and further protein sequence analyses suggests that all six nkl genes fall within the Nkl sub-family of the Saposin family of proteins. Patterns of tissue-specific mRNA expression were asymmetric among the six trout Nkl homologues, with nkl1, nkl3, and nkl-like a & b occurring in immune competent organs such as spleen, gill, intestine and kidney, as well as pineal gland, brain and oocytes. However, nkl2 and nkl4, showed primary abundances in brain, pineal gland and oocyte tissues. Using mRNA sequencing, in whole-body pools of juvenile trout fry (1 g bw) exposed to Flavobacterium psychrophilum infection, we observed modest up-regulation (2–3 fold) of five (nkl 2–4 and nkl-like a & b) of the six nkl mRNAs over the five-day post-challenge time-course. However, no upregulation could be recorded in spleen tissue measured by qPCR in juvenile trout (270 g bw). Using mRNA sequencing again, mRNA abundances were determined in gill of juvenile trout (~57.7 g bw) exposed to various aquaculture stressors. The results indicated that all six nkls (nkl1-4 and nkl-like a and nkl-like b) were downregulated when exposed to high temperature, and that nkl1 was significantly downregulated following salinity challenge. Overall, these newly characterized AMPs may contribute to host innate immunity as they are modulated following pathogen challenge and by physiological stressors.

Recent trends on omics and bioinformatics approaches to study SARS-CoV-2: A bibliometric analysis and mini-review

BackgroundThe successful sequencing of SARS-CoV-2 cleared the way for the use of omics technologies and integrative biology research for combating the COVID-19 pandemic. Currently, many research groups have slowed down their respective projects to concentrate efforts in the study of the biology of SARS-CoV-2. In this bibliometric analysis and mini-review, we aimed to describe how computational methods or omics approaches were used during the first months of the COVID-19 pandemic. MethodsWe analyzed bibliometric data from Scopus, BioRxiv, and MedRxiv (dated June 19th, 2020) using quantitative and knowledge mapping approaches. We complemented our analysis with a manual process of carefully reading the selected articles to identify either the omics or bioinformatic tools used and their purpose. ResultsFrom a total of 184 articles, we found that metagenomics and transcriptomics were the main sources of data to perform phylogenetic analysis aimed at corroborating zoonotic transmission, identifying the animal origin and taxonomic allocation of SARS-CoV-2. Protein sequence analysis, immunoinformatics and molecular docking were used to give insights about SARS-CoV-2 targets for drug and vaccine development. Most of the publications were from China and USA. However, China, Italy and India covered the top 10 most cited papers on this topic. ConclusionWe found an abundance of publications using omics and bioinformatics approaches to establish the taxonomy and animal origin of SARS-CoV-2. We encourage the growing community of researchers to explore other lesser-known aspects of COVID-19 such as virus-host interactions and host response.

Cluster analysis of selected Mycobacterium species using rifampicin resistance DNA-directed RNA polymerase beta subunit (rpoB) gene

Background: Rifampicin is an important drug being one of the first line of drug combination for tuberculosis (TB). Multidrug resistance tuberculosis is a major global health threat in view of the danger it poses to the treatment and control of TB. Rifampicin targets the β-subunit RNA polymerase encoded by the rpoB gene of mycobacteria, thereby inhibiting transcription and, therefore, stopping translation. Mycobacteria with a mutated rpoB gene are resistant to rifampicin effect. In the present study, sequences of rpoB gene of 7 common species of Mycobacterium were used for cluster analysis in order to assess genetic diversity in the bacteria. This was based on the premise that rpoB gene diversity assessment in Mycobacterium spp. may influence rpoB-based drug design in possible cases of co-infection with two or more Mycobacterium spp. Objective: To identify wide spectrum drug target for solving the problem of rifampicin resistance in mycobacteria. Methods and materials: Relevant papers were obtained from literature databases mainly PubMed (www.ncbi.nlm.nih.gov/pubmed/), PubMed Central or PMC (www.ncbi.nlm.nih.gov/pmc) and other sources including Google scholar. Sequences of the Mycobacteria spp. retrieved from Mycobacterium web database platform and MSA performed using MEGA-X softwafre. Results: The results revealed general low gene diversity in Mycobacterium giving 2 main clusters: M. tuberculosis, M. bovis, M. leprae, M. lepromatosis, and M. marium clustered together while M. smegmatis and M. abscessus formed another cluster. Amino acid sequence analysis of rpoB protein sequences indicated more diversity when compared to rpoB gene sequences resulting in a 3-cluster tree. Protein cladogram gave three clusters: M. tuberculosis and M. bovis; M. leprae and M. lepromatosis; M. smegmatis and M. abscessus. M. marinum was simplicifolious. Conclusion: The results of the present bioinformatics analysis suggested that an rpoB gene-targeted drugs might be more effective than protein-targeted drugs in cases of co-infection with Mycobacterium species pathogenic to human.

Protein Sequence Analysis Using the MPI Bioinformatics Toolkit.

The MPI Bioinformatics Toolkit (https://toolkit.tuebingen.mpg.de) provides interactive access to a wide range of the best-performing bioinformatics tools and databases, including the state-of-the-art protein sequence comparison methods HHblits and HHpred. The Toolkit currently includes 35 external and in-house tools, covering functionalities such as sequence similarity searching, prediction of sequence features, and sequence classification. Due to this breadth of functionality, the tight interconnection of its constituent tools, and its ease of use, the Toolkit has become an important resource for biomedical research and for teaching protein sequence analysis to students in the life sciences. In this article, we provide detailed information on utilizing the three most widely accessed tools within the Toolkit: HHpred for the detection of homologs, HHpred in conjunction with MODELLER for structure prediction and homology modeling, and CLANS for the visualization of relationships in large sequence datasets. © 2020 The Authors. Basic Protocol 1: Sequence similarity searching using HHpred Alternate Protocol: Pairwise sequence comparison using HHpred Support Protocol: Building a custom multiple sequence alignment using PSI-BLAST and forwarding it as input to HHpred Basic Protocol 2: Calculation of homology models using HHpred and MODELLER Basic Protocol 3: Cluster analysis using CLANS.

Sequence Features of Mitochondrial Transporter Protein Families.

Mitochondrial carriers facilitate the transfer of small molecules across the inner mitochondrial membrane (IMM) to support mitochondrial function and core cellular processes. In addition to the classical SLC25 (solute carrier family 25) mitochondrial carriers, the past decade has led to the discovery of additional protein families with numerous members that exhibit IMM localization and transporter-like properties. These include mitochondrial pyruvate carriers, sideroflexins, and mitochondrial cation/H+ exchangers. These transport proteins were linked to vital physiological functions and disease. Their structures and transport mechanisms are, however, still largely unknown and understudied. Protein sequence analysis per se can often pinpoint hotspots that are of functional or structural importance. In this review, we summarize current knowledge about the sequence features of mitochondrial transporters with a special focus on the newly included SLC54, SLC55 and SLC56 families of the SLC solute carrier superfamily. Taking a step further, we combine sequence conservation analysis with transmembrane segment and secondary structure prediction methods to extract residue positions and sequence motifs that likely play a role in substrate binding, binding site gating or structural stability. We hope that our review will help guide future experimental efforts by the scientific community to unravel the transport mechanisms and structures of these novel mitochondrial carriers.

First report on the association of ‘Candidatus Phytoplasma asteris’ with lethal wilt disease of coconut (Cocos nucifera L.) in India

Lethal wilt disease of coconut, reported as a disease of unknown etiology as early as 2007, was for the first time found consistently in association with a phytoplasma in diseased coconut trees in Thanjavur, Thiruvarur and Pudukkottai districts in Tamil Nadu on the southeastern coast of India. Nested PCR with phytoplasma-specific universal primers and in silico restriction analysis of 16S rDNA sequences revealed the association of ‘Candidatus Phytoplasma asteris’ (16SrI-B) group phytoplasma, which was confirmed by sequence analysis of translation elongation factor (tuf) and ribosomal protein (rp) genes. Because this disease kills affected palms within 5 months, recommendations are given to arrest the spread of the pathogen to other coconut-growing regions in the country.

SARS-CoV-2 attachment to host cells is possibly mediated via RGD-integrin interaction in a calcium-dependent manner and suggests pulmonary EDTA chelation therapy as a novel treatment for COVID 19

SARS-CoV-2 is a highly contagious virus that has caused serious health crisis world-wide resulting into a pandemic situation. As per the literature, the SARS-CoV-2 is known to exploit humanACE2 receptors (similar toprevious SARS-CoV-1) for gaining entry into the host cell for invasion, infection, multiplication and pathogenesis. However, considering the higher infectivity of SARS-CoV-2 along with the complex etiology and pathophysiological outcomes seen in COVID-19 patients, it seems that there may be an alternate receptor for SARS-CoV-2. I performed comparative protein sequence analysis, database based gene expression profiling, bioinformatics based molecular docking using authentic tools and techniques for unveiling the molecular basis of high infectivity of SARS-CoV-2 as compared to previous known coronaviruses. My study revealed that SARS-CoV-2 (previously known as 2019-nCoV) harbors a RGD motif in its receptor binding domain (RBD) and the motif is absent in all other previously known SARS-CoVs. The RGD motif is well known for its role in cell-attachment and cell-adhesion. My hypothesis is that the SARS-CoV-2 may be (via RGD) exploiting integrins, that have high expression in lungs and all other vital organs, for invading host cells. However, an experimental verification is required. The expression of ACE2, which is a known receptor for SARS-CoV-2, was found to be negligible in lungs. I assume that higher infectivity of SARS-CoV-2 could be due to this RGD-integrin mediated acquired cell-adhesive property. Gene expression profiling revealed that expression of integrins is significantly high in lung cells, in particular αvβ6, α5β1, αvβ8 and an ECM protein, ICAM1. The molecular docking experiment showed the RBD of spike protein binds with integrins precisely at RGD motif in a similar manner as a synthetic RGD peptide binds to integrins as found by other researchers. SARS-CoV-2 spike protein has a number of phosphorylation sites that can induce cAMP, PKC, Tyr signaling pathways. These pathways either activate calcium ion channels or get activated by calcium. In fact, integrins have calcium & metal binding sites that were predicted around and in vicinity of RGD-integrin docking site in our analysis which suggests that RGD-integrins interaction possibly occurs in calcium-dependent manner. The higher expression of integrins in lungs along with their previously known high binding affinity (~KD = 4.0 nM) for virus RGD motif could serve as a possible explanation for high infectivity of SARS-CoV-2. On the contrary, human ACE2 has lower expression in lungs and its high binding affinity (~KD = 15 nM) for spike RBD alone could not manifest significant virus-host attachment. This suggests that besides human ACE2, an additional or alternate receptor for SARS-CoV-2 is likely to exist. A highly relevant evidence never reported earlier which corroborate in favor of RGD-integrins mediated virus-host attachment is an unleashed cytokine storm which causes due to activation of TNF-α and IL-6 activation; and integrins role in their activation is also well established. Altogether, the current study has highlighted possible role of calcium and other divalent ions in RGD-integrins interaction for virus invasion into host cells and suggested that lowering divalent ion in lungs could avert virus-host cells attachment.

SeqEditor: an application for primer design and sequence analysis with or without GTF/GFF files

Abstract Motivation Sequence analyses oriented to investigate specific features, patterns and functions of protein and DNA/RNA sequences usually require tools based on graphic interfaces whose main characteristic is their intuitiveness and interactivity with the user’s expertise, especially when curation or primer design tasks are required. However, interface-based tools usually pose certain computational limitations when managing large sequences or complex datasets, such as genome and transcriptome assemblies. Having these requirments in mind we have developed SeqEditor an interactive software tool for nucleotide and protein sequences’ analysis. Result SeqEditor is a cross-platform desktop application for the analysis of nucleotide and protein sequences. It is managed through a Graphical User Interface and can work either as a graphical sequence browser or as a fasta task manager for multi-fasta files. SeqEditor has been optimized for the management of large sequences, such as contigs, scaffolds or even chromosomes, and includes a GTF/GFF viewer to visualize and manage annotation files. In turn, this allows for content mining from reference genomes and transcriptomes with similar efficiency to that of command line tools. SeqEditor also incorporates a set of tools for singleplex and multiplex PCR primer design and pooling that uses a newly optimized and validated search strategy for target and species-specific primers. All these features make SeqEditor a flexible application that can be used to analyses complex sequences, design primers in PCR assays oriented for diagnosis, and/or manage, edit and personalize reference sequence datasets. Availabilityand implementation SeqEditor was developed in Java using Eclipse Rich Client Platform and is publicly available at https://gpro.biotechvana.com/download/SeqEditor as binaries for Windows, Linux and Mac OS. The user manual and tutorials are available online at https://gpro.biotechvana.com/tool/seqeditor/manual. Supplementary information Supplementary data are available at Bioinformatics online.

A Generalized Iterative Map for Analysis of Protein Sequences.

The similarities comparison of biological sequences is an important task in bioinformatics. The methods of the similarities comparison for biological sequences are divided into two classes: sequence alignment method and alignment-free method. The graphical representation of biological sequences is a kind of alignment-free method, which constitutes a tool for analyzing and visualizing the biological sequences. In this article, a generalized iterative map of protein sequences was suggested to analyze the similarities of biological sequences. Based on the normalized physicochemical indexes of 20 amino acids, each amino acid can be mapped into a point in 5D space. A generalized iterative function system was introduced to outline a generalized iterative map of protein sequences, which can not only reflect various physicochemical properties of amino acids but also incorporate with different compression ratios of the component of a generalized iterative map. Several properties were proved to illustrate the advantage of the generalized iterative map. The mathematical description of the generalized iterative map was suggested to compare the similarities and dissimilarities of protein sequences. Based on this method, similarities/dissimilarities were compared among ND5 protein sequences, as well as ND6 protein sequences of ten different species. By correlation analysis, the ClustalW results were compared with our similarity/dissimilarity results and other graphical representation results to show the utility of our approach. The comparison results show that our approach has better correlations with ClustalW for all species than other approaches and illustrate the effectiveness of our approach. Two examples show that our method not only has good performances and effects in the similarity/dissimilarity analysis of protein sequences but also does not require complex computation.

CIC Is a Mediator of the ERK1/2-DUSP6 Negative Feedback Loop.

SummaryDUSP6 functions as an important negative feedback component of the MAPK/ERK signaling pathway. Although DUSP6 expression is tightly regulated by ERK1/2 signaling, the molecular mechanism of this regulation remains partially understood. In this work, we show that the transcriptional repressor CIC functions downstream of the ERK1/2 signaling to negatively regulate DUSP6 expression. CIC directly represses DUSP6 transcription by binding to three cis-regulatory elements (CREs) in DUSP6 promoter. p90RSK, a downstream target of ERK1/2, phosphorylates CIC at S173 and S301 sites, which creates a 14-3-3 recognition motif, resulting in 14-3-3-mediated nuclear export of CIC and derepression of DUSP6. Finally, we demonstrate that the oncogenic CIC-DUX4 fusion protein acts as a transcriptional activator of DUSP6 and its nuclear/cytoplasmic distribution remains regulated by ERK1/2 signaling. These results complete an ERK1/2/p90RSK/CIC/DUSP6 negative feedback circuit and elucidate the molecular mechanism of how RTK/MAPK signaling harnesses the transcriptional repressor activity of CIC in mammalian cells.

Self-compatibility in peach [Prunus persica (L.) Batsch]: patterns of diversity surrounding the S-locus and analysis of SFB alleles

Self-incompatibility (SI) to self-compatibility (SC) transition is one of the most frequent and prevalent evolutionary shifts in flowering plants. Prunus L. (Rosaceae) is a genus of over 200 species most of which exhibit a Gametophytic SI system. Peach [Prunus persica (L.) Batsch; 2n = 16] is one of the few exceptions in the genus known to be a fully self-compatible species. However, the evolutionary process of the complete and irreversible loss of SI in peach is not well understood and, in order to fill that gap, in this study 24 peach accessions were analyzed. Pollen tube growth was controlled in self-pollinated flowers to verify their self-compatible phenotypes. The linkage disequilibrium association between alleles at the S-locus and linked markers at the end of the sixth linkage group was not significant (P > 0.05), except with the closest markers suggesting the absence of a signature of negative frequency dependent selection at the S-locus. Analysis of SFB1 and SFB2 protein sequences allowed identifying the absence of some variable and hypervariable domains and the presence of additional α-helices at the C-termini. Molecular and evolutionary analysis of SFB nucleotide sequences showed a signature of purifying selection in SFB2, while the SFB1 seemed to evolve neutrally. Thus, our results show that the SFB2 allele diversified after P. persica and P. dulcis (almond) divergence, a period which is characterized by an important bottleneck, while SFB1 diversified at a transition time between the bottleneck and population expansion.