Strict Specificity Research Articles

Potent efficacy of an IgG-specific endoglycosidase against IgG-mediated pathologies.

Endo-β-N-acetylglucosaminidases (ENGases) that specifically hydrolyze the Asn297-linked glycan on immunoglobulin G (IgG) antibodies, the major molecular determinant of fragment crystallizable (Fc) γ receptor (FcγR) binding, are exceedingly rare. All previously characterized IgG-specific ENGases are multi-domain proteins secreted as an immune evasion strategy by Streptococcus pyogenes strains. Here, using in silico analysis and mass spectrometry techniques, we identified a family of single-domain ENGases secreted by pathogenic corynebacterial species that exhibit strict specificity for IgG antibodies. By X-ray crystallographic and surface plasmon resonance analyses, we found that the most catalytically efficient IgG-specific ENGase family member recognizes both protein and glycan components of IgG. Employing invivo models, we demonstrated the remarkable efficacy of this IgG-specific ENGase in mitigating numerous pathologies that rely on FcγR-mediated effector functions, including T and B lymphocyte depletion, autoimmune hemolytic anemia, and antibody-dependent enhancement of dengue disease, revealing its potential for treating and/or preventing a wide range of IgG-mediated diseases in humans.

Tuning ZSM-22 zeolite through NH4F etching enables enhanced performance and tailored product distribution in n-alkane isomerization for sustainable aviation fuels

Isomerization of n-alkane remains a significant strategy for producing high-quality sustainable aviation fuels (SAF). Improving zeolite catalyst performance and optimizing iso-product distribution to meet the SAF specification are still challenging. As the limitation mainly originated from the strict shape selectivity of the microporous zeolite structure, feasible methods were highly demanded. In this work, the NH4F etching approach was utilized to controllably regulate the framework structure of ZSM-22 zeolite, leading to the rational variation in the crystallinity, porosity, morphology, and acidity, which were closely correlated with the etching severity. Compared to the elliptical 10-membered ring micropore mouths of the parent zeolite, the micropore mouths of the etched ZSM-22 zeolite tended to be circular, as observed by HRTEM and strongly supported by Raman, realizing the regulation of zeolite structure. For n-decane isomerization, the etched catalysts exhibited a considerable increase in catalytic performance, surpassing the parent Pt/ZSM-22 catalyst and the highest isomer yield of 82.1% at the conversion of 91.4% was achieved. The optimized iso-product distribution with approximatively equal amounts of several mono-branched isomers and much higher contributions of the originally disfavored isomers was also observed due to the tuned shape selectivity and the balanced bifunctionality. This work presented an efficient method to design zeolite catalysts for linear paraffin isomerization beyond the limit set by the zeolite structure and shape selectivity that meets the strict standard specification for the freezing point of the SAF.

Objective validation of alternative speech test sources for person-to-person speech intelligibility assessments

A sound source that mimics the acoustics characteristics of a human talker is required in objective assessments of speech intelligibility in person-to-person speech communications (PP) scenarios. The few special speech test sources available that meet the strict specifications of the relevant standards are costly and can be inaccessible to practitioners. This can prevent investigations or can lead to non-special and more affordable loudspeakers to be used as alternative sources without knowledge of their suitability. This study evaluates the validity of non-special loudspeakers in PP assessments and supplements a previous preliminary examination by consolidating and expanding early findings. Speech Transmission Index Public Address (STIPA) assessments were conducted employing three representative non-special loudspeakers and one standardized reference speech test source under laboratory conditions. Absolute errors of STIPA measurements were analysed and evaluated against two just perceivable difference (JND) threshold levels. The mean absolute errors obtained for all non-special loudspeakers for almost all scenarios were within one JND of any of the two JND levels. The striking and consistent low level of error found validated the proposition that non-special and affordable loudspeakers may be used as suitable speech sources in pilot or survey-grade speech intelligibility assessments in place of a special standardized speech source when that source is not available, or in full investigations when the relevant standard to adhere to allows the use of those alternative speech sources.

Rewiring protein binding specificity in paralogous DRG/DFRP complexes.

Eukaryotes have two paralogous developmentally regulated GTP-binding (DRG) proteins: DRG1 and DRG2, both of which have a conserved binding partner called DRG family regulatory protein 1 and 2 (DFRP1 and DFRP2), respectively. DFRPs are important for the function of DRGs and interact with their respective DRG via a conserved region called the DFRP domain. Despite being highly similar, DRG1 and DRG2 have strict binding specificity for their respective DFRP. Using AlphaFold generated structure models of the human DRG/DFRP complexes, we have biochemically characterized their interactions and identified interface residues involved in determining specificity. This analysis revealed that as few as five mutations in DRG1 can switch binding from DFRP1 to DFRP2. Moreover, while DFRP1 binding confers increased stability and GTPase activity to DRG1, DFRP2 binding only supports increased stability. Overall, this work provides new insight into the structural determinants responsible for the binding specificities of the DRG/DFRP complexes.

Characterization of a vacuolar importer of secologanin in Catharanthus roseus

Monoterpenoid indole alkaloid (MIA) biosynthesis in Catharanthus roseus is a paragon of the spatiotemporal complexity achievable by plant specialized metabolism. Spanning a range of tissues, four cell types, and five cellular organelles, MIA metabolism is intricately regulated and organized. This high degree of metabolic differentiation requires inter-cellular and organellar transport, which remains understudied. Here, we have characterized a vacuolar importer of secologanin belonging to the multidrug and toxic compound extrusion (MATE) family, named CrMATE1. Phylogenetic analyses of MATEs suggested a role in alkaloid transport for CrMATE1, and in planta silencing in two varieties of C. roseus resulted in a shift in the secoiridoid and MIA profiles. Subcellular localization of CrMATE1 confirmed tonoplast localization. Biochemical characterization was conducted using the Xenopus laevis oocyte expression system to determine substrate range, directionality, and rate. We can confirm that CrMATE1 is a vacuolar importer of secologanin, translocating 1 mM of substrate within 25 min. The transporter displayed strict directionality and specificity for secologanin and did not accept other secoiridoid substrates. The unique substrate-specific activity of CrMATE1 showcases the utility of transporters as gatekeepers of pathway flux, mediating the balance between a defense arsenal and cellular homeostasis.

Single-cell RNA-sequencing reveals a profound immune cell response in human cytomegalovirus-infected humanized mice

Human cytomegalovirus (HCMV) is a common herpesvirus that persistently infects a large portion of the world's population. Despite the robust host immune response, HCMV is able to replicate, evade host defenses, and establish latency throughout the lifespan by developing multiple immunomodulatory strategies, making the studies on the interaction between HCMV infection and host response particularly important. HCMV has a strict host specificity that specifically infects humans. Therefore, most of the in vivo researches of HCMV rely on clinical samples. Fortunately, the establishment of humanized mouse models allows for convenient in-lab animal experiments involving HCMV infection. Single-cell RNA sequencing enables the study of the relationship between viral and host gene expressions at the single-cell level within host cells. In this study, we assessed the gene expression alterations of PBMCs at the single-cell level within HCMV-infected humanized mice, which sheds light onto the virus-host interactions in the context of HCMV infection of humanized mice and provides a valuable dataset for the related researches.

Host range of naturally and artificially evolved symbiotic bacteria for a specific host insect.

Diverse insects are intimately associated with specific symbiotic bacteria, where host and symbiont are integrated into an almost inseparable biological entity. These symbiotic bacteria usually exhibit host specificity, uncultivability, reduced genome size, and other peculiar traits relevant to their symbiotic lifestyle. How host-symbiont specificity is established at the very beginning of symbiosis is of interest but poorly understood. To gain insight into the evolutionary issue, we adopted an experimental approach using the recently developed evolutionary model of symbiosis between the stinkbug Plautia stali and Escherichia coli. Based on the laboratory evolution of P. stali-E. coli mutualism, we selected ΔcyaA mutant of E. coli as an artificial symbiont of P. stali that has established mutualism by a single mutation. In addition, we selected a natural cultivable symbiont of P. stali of relatively recent evolutionary origin. These artificial and natural symbiotic bacteria of P. stali were experimentally inoculated to symbiont-deprived newborn nymphs of diverse stinkbug species. Strikingly, the mutualistic E. coli was unable to establish infection and support growth and survival of all the stinkbug species except for P. stali, uncovering that host specificity can be established at a very early stage of symbiotic evolution. Meanwhile, the natural symbiont was able to establish infection and support growth and survival of several stinkbug species in addition to P. stali, unveiling that a broader host range of the symbiont has evolved in nature. Based on these findings, we discuss what factors are relevant to the establishment of host specificity in the evolution of symbiosis.IMPORTANCEHow does host-symbiont specificity emerge at the very beginning of symbiosis? This question is difficult to address because it is generally difficult to directly observe the onset of symbiosis. However, recent development of experimental evolutionary approaches to symbiosis has brought about a breakthrough. Here we tackled this evolutionary issue using a symbiotic Escherichia coli created in laboratory and a natural Pantoea symbiont, which are both mutualistic to the stinkbug Plautia stali. We experimentally replaced essential symbiotic bacteria of diverse stinkbugs with the artificial and natural symbionts of P. stali and evaluated whether the symbiotic bacteria, which evolved for a specific host, can establish infection and support the growth and survival of heterospecific hosts. Strikingly, the artificial symbiont showed strict host specificity to P. stali, whereas the natural symbiont was capable of symbiosis with diverse stinkbugs, which provide insight into how host-symbiont specificity can be established at early evolutionary stages of symbiosis.

Identification, expression, and characterization of a marine-derived chitinase Ce0303 from Chitiniphilus eburneus YS-30 with exo- and endo-hydrolytic properties

N-acetyl-oligosaccharides exhibit antioxidant and antibacterial activities. However, the low catalytic efficiency of chitinase on crystalline chitin hinders the eco-friendly production of N-acetyl-oligosaccharides. A marine-derived chitinase-producing strain Chitiniphilus eburneus YS-30 was screened in this study. The genome of C. eburneus YS-30 spans 4,522,240 bp, with a G + C content of 63.96 % and 4244 coding genes. Among the chitinases secreted by C. eburneus YS-30, Ce0303 showed the highest content at 19.10 %, with a molecular weight of 73.5 kDa. Recombinant Ce0303 exhibited optimal activity at 50 °C and pH 5.0, maintaining stability across pH 4.0–10.0. Ce0303 demonstrated strict substrate specificity, with a specific activity toward colloidal chitin of 6.41 U mg−1, Km of 2.34 mg mL−1, and kcat of 3.27 s−1. The specific activity of Ce0303 toward α-chitin was 18.87 % of its activity on colloidal chitin. Ce0303 displayed both exo- and endo-hydrolytic properties, primarily producing (GlcNAc)1–3 from colloidal chitin. The structure of Ce0303 includes one catalytic domain and two chitin-binding domains. Docking results revealed that the GlcNAc at −1 subsite formed two hydrogen bonds with conserved Trp380. The hydrolytic properties of Ce0303 will provide technical support for the comprehensive utilization of crustacean raw materials.

Following the Evolutionary Paths of Dscam1 Proteins toward Highly Specific Homophilic Interactions.

Many adhesion proteins, evolutionarily related through gene duplication, exhibit distinct and precise interaction preferences and affinities crucial for cell patterning. Yet, the evolutionary paths by which these proteins acquire new specificities and prevent cross-interactions within their family members remain unknown. To bridge this gap, this study focuses on Drosophila Down syndrome cell adhesion molecule-1 (Dscam1) proteins, which are cell adhesion proteins that have undergone extensive gene duplication. Dscam1 evolved under strong selective pressure to achieve strict homophilic recognition, essential for neuronal self-avoidance and patterning. Through a combination of phylogenetic analyses, ancestral sequence reconstruction, and cell aggregation assays, we studied the evolutionary trajectory of Dscam1 exon 4 across various insect lineages. We demonstrated that recent Dscam1 duplications in the mosquito lineage bind with strict homophilic specificities without any cross-interactions. We found that ancestral and intermediate Dscam1 isoforms maintained their homophilic binding capabilities, with some intermediate isoforms also engaging in promiscuous interactions with other paralogs. Our results highlight the robust selective pressure for homophilic specificity integral to the Dscam1 function within the process of neuronal self-avoidance. Importantly, our study suggests that the path to achieving such selective specificity does not introduce disruptive mutations that prevent self-binding but includes evolutionary intermediates that demonstrate promiscuous heterophilic interactions. Overall, these results offer insights into evolutionary strategies that underlie adhesion protein interaction specificities.

Molecular Modification Strategies of Nitrilase for Its Potential Application in Agriculture.

Some feed source plants will produce secondary metabolites such as cyanogenic glycosides during metabolism, which will produce some poisonous nitrile compounds after hydrolysis and remain in plant tissues. The consumption of feed-source plants without proper treatment affect the health of the animals' bodies. Nitrilases can convert nitriles and have been used in industry as green biocatalysts. However, due to their bottleneck problems, their application in agriculture is still facing challenges. Acid-resistant nitrilase preparations, high-temperature resistance, antiprotease activity, strong activity, and strict reaction specificity urgently need to be developed. In this paper, the application potential of nitrilase in agriculture, especially in feed processing industry was explored, the source properties and catalytic mechanism of nitrilase were reviewed, and modification strategies for nitrilase application in agriculture were proposed to provide references for future research and application of nitrilase in agricultural and especially in the biological feed scene.

Identification of a novel glycoside hydrolase family 8 xylanase from Deinococcus geothermalis and its application at low temperatures.

Xylanase is the most important hydrolase in the xylan hydrolase system, the main function of which is β-1,4-endo-xylanase, which randomly cleaves xylans to xylo-oligosaccharides and xylose. Xylanase has wide ranging of applications, but there remains little research on the cold-adapted enzymes required in some low-temperature industries. Glycoside hydrolase family 8 (GH8) xylanases have been reported to have cold-adapted enzyme activity. In this study, the xylanase gene dgeoxyn was excavated from Deinococcus geothermalis through sequence alignment. The recombinant xylanase DgeoXyn encodes 403 amino acids with a theoretical molecular weight of 45.39kDa. Structural analysis showed that DgeoXyn has a (α/α)6-barrel fold structure typical of GH8 xylanase. At the same time, it has strict substrate specificity, is only active against xylan, and its hydrolysis products include xylobiose, xylotrinose, xytetranose, xylenanose, and a small amount of xylose. DgeoXyn is most active at 70℃ and pH 6.0. It is very stable at 10, 20, and 30℃, retaining more than 80% of its maximum enzyme activity. The enzyme activity of DgeoXyn increased by 10% after the addition of Mn2+ and decreased by 80% after the addition of Cu2+. The Km and Vmax of dgeox were 42mg/ml and 20,000 U/mg, respectively, at a temperature of 70℃ and pH of 6.0 using 10mg/ml beechwood xylan as the substrate. This research on DgeoXyn will provide a theoretical basis for the development and application of low-temperature xylanase.

Therapeutic effects of a novel synthetic α-secretase.

Excessive accumulation of amyloid-β (Aβ) has been associated with the pathogenesis of Alzheimer's disease (AD). Clinical studies have further proven that elimination of Aβ can be a viable therapeutic option. In the current study, we conceptualized a fusion membrane protein, referred to as synthetic α-secretase (SAS), that can cleave amyloid precursor protein (APP) and Aβ specifically at the α-site. In mammalian cells, SAS indeed cleaved APP and Aβ at the α-site. Overexpression of SAS in the hippocampus was achieved by direct injection of recombinant adeno-associated virus serotype 9 (AAV9) that expresses SAS (AAV9-SAS) into the bilateral ventricles of mouse brains. SAS enhanced the non-amyloidogenic processing of APP, thus reducing the levels of soluble Aβ and plaques in the 5xFAD mice. In addition, SAS significantly attenuated the cognitive deficits in 5xFAD mice, as demonstrated by novel object recognition and Morris water maze tests. Unlike other Aβ-cleaving proteases, SAS has highly strict substrate specificity. We propose that SAS can be an efficient modality to eliminate excessive Aβ from diseased brains.

Mechanism-Guided Computational Design Drives meso-Diaminopimelate Dehydrogenase to Efficient Synthesis of Aromatic d-amino Acids.

Aromatic d-amino acids (d-AAs) play a pivotal role as important chiral building blocks and key intermediates in fine chemical and drug synthesis. Meso-diaminopimelate dehydrogenase (DAPDH) serves as an excellent biocatalyst in the synthesis of d-AAs and their derivatives. However, its strict substrate specificity and the lack of efficient engineering methods have hindered its widespread application. Therefore, this study aims to elucidate the catalytic mechanism underlying DAPDH from Proteus vulgaris (PvDAPDH) through the examination of its crystallographic structure, computational simulations of potential energies and molecular dynamics simulations, and site-directed mutagenesis. Mechanism-guided computational design showed that the optimal mutant PvDAPDH-M3 increased specific activity and catalytic efficiency (kcat/Km) for aromatic keto acids up to 124-fold and 92.4-fold, respectively, compared to that of the wild type. Additionally, it expanded the substrate scope to 10 aromatic keto acid substrates. Finally, six high-value-added aromatic d-AAs and their derivatives were synthesized using a one-pot three-enzyme cascade reaction, exhibiting a good conversion rate ranging from 32 to 84% and excellent stereoselectivity (enantiomeric excess >99%). These findings provide a potential synthetic pathway for the green industrial production of aromatic d-AAs.

Identification of Salmonella Enterica Serovar Typhi DNA by loop-mediated isothermal amplification with fluorescent detection

Introduction. Real-time PCR may be used along with loop isothermal amplification method (LAMP) allowing to conduct the study in 30–40 minutes to diagnose typhoid fever. Several LAMP assay variations for detecting Salmonella enterica serovar Typhi have been described. The studies report that relevant primers were tested on strains specific for Malaysia and China. We attempted to evaluate the LAMP primers described above for identifying S. Typhi strains specific for the Russian Federation and compare their sensitivity and specificity with each other. Materials and methods. A comparative in silico analysis of target sequences was carried out both in the open NCBI database and among the genetic sequences of collection strains at the St. Petersburg Pasteur Institute. Several sets of primers for LAMP amplification of various S. Typhi genome regions were tested. The tested primers amplify the following fragments: SalTyp1 — region of the STY1607 gene, SalTyp2 — region of the STY2879 gene, SalTyp3 — region of the STBHUCCB_38510 gene of the PapD chaperone. Results. In silico analysis of LAMP primers showed that only the SalTyp 3 set has strict specificity for Salmonella enterica serovar Typhi. For the SalTyp 1 and SalTyp 2 an opportunity of false-positive reactions with some E. coli strains was shown. A LAMP method for DNA fluorescent detection of the typhoid fever causative agent was chosen. Assay has been based on a marker gene termed STBHUCCB_38510 and amplification with six specific primers. The detection limit was 20 copies/reaction in reference plasmids and the reaction time lasted for 35 minutes. The specificity of the method was tested on DNA specimens of 20 S. Typhi isolates and 90 strains of other heterologous bacteria from 24 different species. No false positive or false negative results were identified. Conclusion. The developed method can be used in clinical practice for laboratory confirmation of typhoid fever diagnosis as a part of epidemiological monitoring of environmental objects as well as food products.

Deciphering microbial communities of three Savoyard raw milk cheeses along ripening and regarding the cheese process

Different Savoyard cheeses are granted with PDO (Protected Designation or Origin) and PGI (Protected Geographical Indication) which guarantees consumers compliance with strict specifications. The use of raw milk is known to be crucial for specific flavor development. To unravel the factors influencing microbial ecosystems across cheese making steps, according to the seasonality (winter and summer) and the mode of production (farmhouse and dairy factory ones), gene targeting on bacteria and fungus was used to have a full picture of 3 cheese making technologies, from the raw milk to the end of the ripening. Our results revealed that Savoyard raw milks are a plenteous source of biodiversity together with the brines used during the process, that may support the development of specific features for each cheese. It was shown that rinds and curds have very contrasted ecosystem diversity, composition, and evolution. Ripening stage was selective for some bacterial species, whereas fungus were mainly ubiquitous in dairy samples. All ripening stages are impacted by the type of cheese technologies, with a higher impact on bacterial communities, except for fungal rind communities, for which the technology is the more discriminant. The specific microorganism's abundance for each technology allow to see a real bar-code, with more or less differences regarding bacterial or fungal communities. Bacterial structuration is shaped mainly by matrices, differently regarding technologies while the influence of technology is higher for fungi. Production types showed 10 differential bacterial species, farmhouses showed more ripening taxa, while dairy factory products showing more lactic acid bacteria. Meanwhile, seasonality looks to be a minor element for the comprehension of both microbial ecosystems, but the uniqueness of each dairy plant is a key explicative feature, more for bacteria than for fungus communities.

Characterization of Solitalea canadensis α-mannosidase with specific activity towards α1,3-Mannosidic linkages

A recombinant exo-α-mannosidase from Solitalea canadensis (Sc3Man) has been characterized to exhibit strict specificity for hydrolyzing α1,3-mannosidic linkages located at the non-reducing end of glycans containing α-mannose. Enzymatic characterization revealed that Sc3Man operates optimally at a pH of 5.0 and at a temperature of 37 °C. The enzymatic activity was notably enhanced twofold in the presence of Ca2+ ions, emphasizing its potential dependency on this metal ion, while Cu2+ and Zn2+ ions notably impaired enzyme function. Sc3Man was able to efficiently cleave the terminal α1,3 mannose residue from various high-mannose N-glycan structures and from the model glycoprotein RNase B. This work not only expands the categorical scope of bacterial α-mannosidases, but also offers new insight into the glycan metabolism of S. canadensis, highlighting the enzyme's utility for glycan analysis and potential biotechnological applications.

Molecular cloning and biochemical characterization of indole-3-acetic acid methyltransferase from Japanese star anise (Illicium anisatum).

SABATH proteins methylate the carboxyl groups or nitrogen atoms of small plant molecules and play important roles in many developmental processes and plant defense responses. Previous studies have shown that indole-3-acetic acid (IAA) carboxyl methyltransferase (IAMT), a member of the SABATH methyltransferase family, converts IAA into its methyl ester (Me-IAA). We used RNA-seq analysis to identify a putative IAMT gene, IaIAMT, in the ancient angiosperm Illicium anisatum. Functional characterization of the recombinant IaIAMT protein expressed in Escherichia coli showed the highest level of activity with IAA, whereas indole-3-propionic acid and indole-3-butyric acid were not used as substrates. The apparent Km value of IaIAMT using IAA as a substrate was determined to be 122 µM. Phylogenetic analysis and structural modeling of IaIAMT suggested that IaIAMT evolved independently from IAMTs isolated from other plant species, whereas strict substrate specificity toward IAA was conserved in Illicium species, as observed in other plants.

Structural and functional analysis of SpGlu64A: a novel glycoside hydrolase family 64 laminaripentaose-producing β-1,3-glucanase from Streptomyces pratensis.

Laminaripentaose (L5)-producing β-1,3-glucanases can preferentially cleave the triple-helix curdlan into β-1,3-glucooligosaccharides, especially L5. In this study, a newly identified member of the glycoside hydrolase family 64, β-1,3-glucanase from Streptomyces pratensis (SpGlu64A), was functionally and structurally characterized. SpGlu64A shared highest identity (30%) with a β-1,3-glucanase from Streptomyces matensis. The purified SpGlu64A showed maximal activity at pH 7.5 and 50 °C, and exhibited strict substrate specificity toward curdlan (83.1 U·mg-1). It efficiently hydrolyzed curdlan to produce L5 as the end product. The overall structure of SpGlu64A consisted of a barrel domain and a mixed (α/β) domain, which formed an unusually wide groove with a crescent-like structure. In the two complex structures (SpGlu64A-L3 and SpGlu64A-L4), two oligosaccharide chains were captured and the triple-helical structure was relatively compatible with the wide groove, which suggested the possibility of binding to the triple-helical β-1,3-glucan. A catalytic framework (β6-β9-β10) and the steric hindrance formed by the side chains of residues Y161, N163, and H393 in the catalytic groove were predicted to complete the exotype-like cleavage manner. On the basis of the structure, a fusion protein with the CBM56 domain (SpGlu64A-CBM) and a mutant (Y161F; by site-directed mutation) were obtained, with 1.2- and 1.7-fold increases in specific activity, respectively. Moreover, the combined expression of SpGlu64A-CBM and -Y161F improved the enzyme activity by 2.63-fold. The study will notonly be helpful in understanding the reaction mechanism of β-1,3-glucanases but will also provide a basis for further enzyme engineering.

The Utilization of Biomarkers in Stress-Related Diseases

Various internal and external factors negatively affect the homeostatic balance of the individual at the whole-body level and cause a state of stress. Stress affects the state of comfort and causes changes in energy consumption mechanisms to combat its effects. Individuals may be immunocompromised, susceptible to pathogens. Stress biomarkers play an important role in the prognosis of stress-related diseases and disorders, and therapy. In addition, different components have been identified as potent mediators of cardiovascular, central nervous system, hepatic, and nephrological disorders, which can also be used to evaluate these conditions precisely, but with strict validation and specificity. Considerable scientific progress has been made in the quantization and application of these biomarkers. This review describes current advances in biomarker identification, their prognostic and therapeutic value. Articles review were carried out using the scooping review method by identifying research publications that match the theme through an online search system. The result of this review is that 31 stress-related biomarkers have an important role in the prognosis of stress-related diseases and disorders, and have been identified as potent mediators of cardiovascular, central nervous system, hepatic, and nephrological disorders. From this review, it can be concluded that chronic stress can cause pathological responses in the body due to disruption of body homeostasis in the long term, resulting in changes in the value of physiological biomarkers of the body. The specific biomarkers that are affected then can be used as diagnostic or prognostic biomarkers.

A distinctive family of L,D-transpeptidases catalyzing L-Ala-mDAP crosslinks in Alpha- and Betaproteobacteria

The bacterial cell-wall peptidoglycan is made of glycan strands crosslinked by short peptide stems. Crosslinks are catalyzed by DD-transpeptidases (4,3-crosslinks) and LD-transpeptidases (3,3-crosslinks). However, recent research on non-model species has revealed novel crosslink types, suggesting the existence of uncharacterized enzymes. Here, we identify an LD-transpeptidase, LDTGo, that generates 1,3-crosslinks in the acetic-acid bacterium Gluconobacter oxydans. LDTGo-like proteins are found in Alpha- and Betaproteobacteria lacking LD3,3-transpeptidases. In contrast with the strict specificity of typical LD- and DD-transpeptidases, LDTGo can use non-terminal amino acid moieties for crosslinking. A high-resolution crystal structure of LDTGo reveals unique features when compared to LD3,3-transpeptidases, including a proline-rich region that appears to limit substrate access, and a cavity accommodating both glycan chain and peptide stem from donor muropeptides. Finally, we show that DD-crosslink turnover is involved in supplying the necessary substrate for LD1,3-transpeptidation. This phenomenon underscores the interplay between distinct crosslinking mechanisms in maintaining cell wall integrity in G. oxydans.