Filamentous Temperature-sensitive Protein Research Articles

Erythromycin-metal complexes: One-step synthesis, molecular docking analysis and antibacterial proficiency against pathogenic strains

The study focused on the extraction of free erythromycin from commercially manufactured tablets and the use of metal salts to synthesize erythromycin-metal complexes, specifically involving silver (Ag), nickel (Ni), cobalt (Co), and copper (Cu). The synthesis was confirmed through various methods, including elemental analysis, thermogravimetric analysis, Fourier-transform infrared (FTIR), and UV–visible spectroscopy. The microbiological investigation involved Salmonella typhi, Escherichia coli, Staphylococcus aureus, Bacillus cereus, Candida albicans, and Microsporum canis as test organisms. The NCCLS broth microdilution reference method was used to determine the minimum fungicidal concentration and minimum inhibitory concentration of the complexes. The synthesized complexes were highly effective against a variety of fungi and bacteria, with compound Ery-Cu having MIC as low as 1.56 mg/mL, Ery-Cu and Ery-Ni with MBCs of 6.25 mg/mL and Ery-Cu having MFC of 6.25 mg/mL. Dose-dependent inhibitory effects were found upon examination of the antimicrobial susceptibility of specific complexes (Cu, Ni, Co and Ag) at varying concentrations of 100, 50, 25 and 12.5 mm/mL. Antibiotic susceptibility testing revealed efficacy against the tested pathogens. The study suggests that the synthesis of erythromycin-metal complexes, coupled with their antibacterial effectiveness against a diverse spectrum of bacteria and fungi, as they showed promising inhibitory properties when tested against a range of test species (Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Candida albicans, and Microsporum canis), could lead to the development of innovative antibacterial agents. Molecular docking simulations were used to examine the interactions between metal complexes with proteins filamentous temperature-sensitive protein Z and lanosterol 14α-demethylase. The study highlights the need for further exploration in pharmaceutical research.

Application of natural-products repurposing strategy to discover novel FtsZ inhibitors: Bactericidal evaluation and the structure-activity relationship of sanguinarine and its analogs

The novel bactericidal target—filamentous temperature-sensitive protein Z (FtsZ)—has drawn the attention of pharmacologists to address the emerging issues with drug/pesticide resistance caused by pathogenic bacteria. To enrich the structural diversity of FtsZ inhibitors, the antibacterial activity and structure-activity relationship (SAR) of natural sanguinarine and its analogs were investigated by using natural-products repurposing strategy. Notably, sanguinarine and chelerythrine exerted potent anti-Xanthomonas oryzae pv. oryzae (Xoo) activity, with EC50 values of 0.96 and 0.93 mg L−1, respectively, among these molecules. Furthermore, these two compounds could inhibit the GTPase activity of XooFtsZ, with IC50 values of 241.49 μM and 283.14 μM, respectively. An array of bioassays including transmission electron microscopy (TEM), fluorescence titration, and Fourier transform infrared spectroscopy (FT-IR) co-verified that sanguinarine and chelerythrine were potential XooFtsZ inhibitors that could interfere with the assembly of FtsZ filaments by inhibiting the GTPase hydrolytic ability of XooFtsZ protein. Additionally, the pot experiment suggested that chelerythrine and sanguinarine demonstrated excellent curative activity with values of 59.52% and 54.76%, respectively. Excitedly, these two natural compounds also showed outstanding druggability, validated by acceptable drug-like properties and low toxicity on rice. Overall, the results suggested that chelerythrine was a new and potential XooFtsZ inhibitor to develop new bactericide and provided important guiding values for rational drug design of FtsZ inhibitors. Notably, our findings provide a novel strategy to discover novel, promising and green bacterial compounds for the management of plant bacterial diseases.

Bioactive profiling of Rumex vesicarius L. from the Hail region of Saudi Arabia: a study on its phytochemical and elemental analysis, antibiofilm, antibacterial, antioxidant properties, and molecular docking analysis.

Rumex vesicarius is a wild leafy plant belonging to the family Polygonaceae, renowned for its therapeutic benefits. The genus Rumex comprises approximately 150 species distributed globally. The study aimed to investigate the biological activities of R. vesicarius using in vitro and in silico methods. Rumex vesicarius was collected from the mountains in Hail and extracted with methanol. The phytochemical composition was qualitatively determined using colorimetric detection methods. Additional analyses included elemental analysis, in silico docking, antioxidant, antibacterial, and anti-biofilm properties. The extract contained various classes of phytochemicals, including flavonoids, phenolics, tannins, terpenes, and saponins. Sixteen constituents were identified through molecular docking, revealing inhibition against the filamentous temperature-sensitive protein Z (FtsZ), a crucial factor in bacterial cell division. Six compounds exhibited low binding scores ranging from -8.3 to -5.0 kcal/mol, indicating efficient interaction at the active site. Elemental analysis identified 15 elements, with potassium being the most abundant, followed by calcium, aluminum, silicon, iron, phosphorus, sulfur, magnesium, titanium, strontium, zinc, manganese, bromine, and chromium. Antioxidant analysis revealed significant properties at lower concentrations compared to ascorbic acid, butylated hydroxytoluene, and β-carotene. Antibacterial analysis demonstrated inhibitory effects on Bacillus subtilis MTCC121 and Pseudomonas aeruginosa MTCC 741, with inhibition zones of 13.67 ± 1.0 mm and 11.50 ± 1.0 mm, respectively. The MIC and MBC values ranged from 250 to 500 μg/mL. R. vesicarius also exhibited anti-biofilm activity. Wild-grown R. vesicarius from the mountains of Hail is rich in bioactive phytochemicals and essential minerals, exhibiting notable antioxidant and antibacterial properties.

Targeting Mycobacterium tuberculosis: Synthesis, in vitro and in silico evaluation of novel N1 -(benzo[d]oxazol-2-yl)-N4 -arylidine compounds.

The development of novel antimycobacterial agents is an urgent challenge to eradicate the increasing emergence and rapid spread of multidrug-resistant strains. Filamentous temperature-sensitive protein Z (FtsZ) is a crucial cell division protein. Alteration of FtsZ assembly leads to cell division inhibition and cell death. To find novel antimycobacterial agents, a series of N1 -(benzo[d]oxazol-2-yl)-N4 -arylidine compounds 5a-o were synthesized. The activity of the compounds was evaluated against drug-sensitive, multidrug-resistant, and extensive-drug-resistant Mycobacterium tuberculosis. Compounds 5b, 5c, 5l, 5m, and 5o showed promising antimycobacterial activity with minimum inhibitory concentrations (MIC) in the range of 0.48-1.85 µg/mL and with low cytotoxicity against human nontumorigenic lung fibroblast WI-38 cells. The activity of the compounds 5b, 5c, 5l, 5m, and 5o was evaluated against bronchitis causing-bacteria. They exhibited good activity against Streptococcus pneumoniae, Klebsiella pneumoniae, Mycoplasma pneumonia, and Bordetella pertussis. Molecular dynamics simulations of Mtb FtsZ protein-ligand complexes identified the interdomain site as the binding site and key interactions. ADME prediction indicated that the synthesized compounds have drug-likeness. The density function theory studies of 5c, 5l, and 5n were performed to investigate E/Z isomerization. Compounds 5c and 5l are present as E-isomers and 5n as an E/Z mixture. Our experimental outcomes provide an auspicious lead for the design of more selective and potent antimycobacterial drugs.

The Antibacterial Activity of 1,2,3-triazole- and 1,2,4-Triazole-containing Hybrids against Staphylococcus aureus: An Updated Review (2020- Present).

Staphylococcus aureus (S. aureus), a prominent, highly contagious nosocomial and community- acquired bacterial pathogen, can cause a broad spectrum of diseases. Antibiotic-resistant S. aureus strains, which pose potential causes of morbidity and mortality, have continuously emerged in recent years, calling for novel anti-S. aureus agents. 1,2,3-triazole and 1,2,4-triazole, the bioisostere of amides, esters, and carboxylic acids, are potent inhibitors of DNA gyrase, topoisomerase IV, efflux pumps, filamentous temperature-sensitive protein Z, and penicillin-binding protein. In particular, 1,2,3-triazole- and 1,2,4-triazole-containing hybrids have the potential to exert dual or multiple antibacterial mechanisms of action. Moreover, 1,2,3-triazole-cephalosporin hybrid cefatrizine, 1,2,3- triazole-oxazolidinone hybrid radezolid, and 1,2,4-triazolo[1,5-a]pyrimidine hybrid essramycin, have already been used in clinical practice to treat bacterial infections. Hence, 1,2,3-triazole- and 1,2,4- triazole-containing hybrids possess promising broad-spectrum antibacterial activity against diverse clinically significant organisms, including drug-resistant forms. This review is an update on the latest development of 1,2,3-triazole- and 1,2,4-triazole-containing hybrids with anti-S. aureus activity, covering articles published between January 2020 and July 2021.

The discovery of natural 4'-demethylepipodophyllotoxin from renewable Dysosma versipellis species as a novel bacterial cell division inhibitor for controlling intractable diseases in rice

Natural products (NPs) are inexhaustible wellsprings for new agrochemicals discovery. To excavate novel natural products-based antibacterial leads or candidates potentially targeting FtsZ (filamentous temperature-sensitive protein Z) which is widely regarded as a promising antibacterial target for novel drug discovery, herein, a rapid and efficient screening platform was initially established to disclose the potential FtsZ inhibitors from a variety of commercial natural products. Screening results revealed that 4'-demethylepipodophyllotoxin (DMEP) from renewable Dysosma versipellis (D. versipellis) species could distinctly decrease the XooFtsZ’ GTPase activity and afforded a ponderable bacteriostatic effect (EC50 =38.7 mg L-1) against Xanthomonas oryzae pv. oryzae (Xoo). Further explorations found that DMEP could disorganize the assembly dynamics of XooFtsZ, and thereby yielding long and filamentous Xoo cells from the transmission electron microscopic and fluorescence microscopic imaging. Molecular docking study showed that DMEP displayed strong interactions with Asp38 and Arg205 residues of XooFtsZ, indicating that a natural potential FtsZ inhibitor was discovered gradually. The following bioassay result against rice bacterial blight in vivo presented good curative activity (50.0% at 200 mg L−1) and protective activity (46.8% at 200 mg L−1). Given that natural DMEP has many sites for structural modification, therefore, it can concurrently serve as a novel lead compound for exploring highly bioactive FtsZ inhibitors based on the molecular skeleton of DMEP.

Nutraceutical potential of Pennisetum typhoides microgreens: In vitro evaluation of antioxidant and antibacterial activities and in silico Staphylococcus aureus FtsZ inhibition

The objective of this study was to evaluate and identify the components of microgreens harvested from Pennisetum typhoides (Pearl millet) for their antioxidant and antimicrobial activities besides finding the possible mechanism of inhibition of Staphylococcus aureus filamentous temperature-sensitive protein Z (FtsZ) in-silico. Initially, methanolic extracts of microgreens from five to ten days post germination (dpg) stages of two pearl millet varieties (PC-383 and PC-612) were compared for total phenolics content (TPC), total flavonoids content (TFC) and antioxidant activity using in vitro assays: DPPH• and ABTS+ radical scavenging. Eighth dpg showed the highest antioxidant activity and best correlation with the amount of phytochemicals. Further, its sequential extracts with solvents of increasing polarities were compared for antioxidant potential. Antibacterial activity was tested using Kirby-Bauer disc diffusion method and minimum inhibitory concentration (MIC) was determined using broth macrodilution method. Aqueous extracts (AE) had highest antioxidant activity and lowest MIC against S. aureus (0.125 mg/ml). Phenolic acids composition of AE was determined by ultra-fast liquid chromatography (UFLC) followed by docking with S. aureus FtsZ protein. Chlorogenic acid (CHA) was found to have lowest binding energy (ΔG -9.21 kcal/mol) and lowest inhibition constant (Ki 176.05 nM). In comparison with a known inhibitor of S. aureus FtsZ (PC-190723), molecular dynamics simulation studies depicted its stable interaction as assessed via root mean square deviation (RMSD), root mean square fluctuation (RMSF) and the number of hydrogen bonds were found comparable. This novel finding points toward further exploring and utilizing these microgreens for bioactives with nutraceutical potential.

Conformational Flexibility of A Highly Conserved Helix Controls Cryptic Pocket Formation in FtsZ

Mycobacterium tuberculosis is responsible for more than 1.6 million deaths each year. One potential antibacterial target in M. tuberculosis is filamentous temperature sensitive protein Z (FtsZ), which is the bacterial homologue of mammalian tubulin, a validated cancer target. M. tuberculosis FtsZ function is essential, with its inhibition leading to arrest of cell division, elongation of the bacterial cell and eventual cell death. However, the development of potent inhibitors against FtsZ has been a challenge owing to the lack of structural information. Here we report multiple crystal structures of M. tuberculosis FtsZ in complex with a coumarin analogue. The 4-hydroxycoumarin binds exclusively to two novel cryptic pockets in nucleotide-free FtsZ, but not to the binary FtsZ-GTP or GDP complexes. Our findings provide a detailed understanding of the molecular basis for cryptic pocket formation, controlled by the conformational flexibility of the H7 helix, and thus reveal an important structural and mechanistic rationale for coumarin antibacterial activity.

Genome-Wide Analysis of Tubulin Gene Family in Cassava and Expression of Family Member FtsZ2-1 during Various Stress.

Filamentous temperature-sensitive protein Z (Tubulin/FtsZ) family is a group of conserved GTP-binding (guanine nucleotide-binding) proteins, which are closely related to plant tissue development and organ formation as the major component of the cytoskeleton. According to the published genome sequence information of cassava (Manihot esculenta Crantz), 23 tubulin genes (MeTubulins) were identified, which were divided into four main groups based on their type and phylogenetic characteristics. The same grouping generally has the same or similar motif composition and exon–intron structure. Collinear analysis showed that fragment repetition event is the main factor in amplification of cassava tubulin superfamily gene. The expression profiles of MeTubulin genes in various tissue were analyzed, and it was found that MeTubulins were mainly expressed in leaf, petiole, and stem, while FtsZ2-1 was highly expressed in storage root. The qRT-PCR results of the FtsZ2-1 gene under hormone and abiotic stresses showed that indole-3-acetic acid (IAA) and gibberellin A3 (GA3) stresses could significantly increase the expression of the FtsZ2-1 gene, thereby revealing the potential role of FtsZ2-1 in IAA and GA3 stress-induced responses.

In silico and in vitro Study on the Inhibition of FtsZ Protein of Staphylococcus aureus by Active Compounds from Andrographis paniculata

Both organ systems, ranging from isolated skin infections to life-threatening systemic infections are implicated in the gram-positive bacterium Staphylococcus aureus, responsible for a wide range of human diseases. Filamentous temperature-sensitive protein Z (FtsZ) is a protein encoded by the FtsZ gene that assembles into a Z-ring at the potential site of the septum of bacterial cell division. Structurally, FtsZ is a eukaryotic tubulin homolog that has a low resemblance in sequence; that makes it possible to acquire FtsZ inhibitors without impacting the division of eukaryotic cells. Hence, in our research, we tried to test compounds from the Andrographis paniculata plant using molecular docking and dynamic simulations as an efficient inhibitor of the S. aureus FtsZ protein. We have picked Andrographolide, Neoandrographolide, Andrograpanin, and 14-deoxyandrographolide as the best inhibitor for the FtsZ protein based on the docking results. In terms of docking score and hydrogen bond interaction, Andrographolide exhibited very good results relative to all other compounds. So the docked Andrographolide-FtsZ protein complex has been further analysed through simulation of molecular dynamics. Results of MD simulations indicate that the compound was excellent at linking the target protein and preserving firm connexions throughout the protein backbone structures, creating very little negligible disruption. Finally, the in vitro antimicrobial activity findings of these four compounds also showed that selected compounds may serve as a potent S.aureus inhibitor.

Anti-Tuberculosis Activity in Punica granatum: In silico Validation and Identification of Lead Molecules

Discovery of novel drug against tuberculosis is inevitable since resistant bacterial strains are evolved against existing drugs and rapidly active single drug in short period is necessary for effective treatment. When compared to synthetic drugs, natural drugs particularly phytochemicals induce less side effects and long term stability. In Indian traditional medicine, several plant species have been used for treating tuberculosis and each plant species contains a plethora of phytochemicals. The efficacy of such treatment system and identification of the phytochemical with drug activity from plants has been seldom investigated scientifically. In this backdrop, the authors have validated the efficacy of anti-tuberculosis activity and identified lead molecule from a widely used plant species against several disease including tuberculosis, viz Punica granatum L. The four promising target proteins viz mycolyltransferase antigen protein 85C involved in cord factor synthesis, filamentous temperature sensitive protein Z involved in bacterial cell division, pantothenate kinase involved in co-enzyme A pathway and decaprenylphosphoryl β-D-ribofuranose-2 epimerase involved in the synthesis of virulent factor arabinan were docked with 243 phytochemicals derived from Punica granatum. The docked molecules having binding energy ≤-6 kcal/ mol were considered as active/hit molecules. The docked results showed that out of 243 phytochemicals, 126 have inhibitory activity on all selected target proteins. Further docking study using Glide and absorption, distribution, metabolism, excretion and toxicity studies revealed that the compound derived from the lowers, pomegranatate can be recommended as the best lead compound against tuberculosis.

1,2,4-Triazole hybrids with potential antibacterial activity against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) has developed numerous mechanisms of virulence and strategies to evade the human immune system, and it can be transmitted between humans, animals, and the environment. Thus, MRSA is an important cause of morbidity and mortality in both hospitals and in the community, creating an urgent demand for the development of novel anti-MRSA candidates. The 1,2,4-triazole nucleus is a bioisostere of amide, ester, and carboxylic acid, and the 1,2,4-triazole ring is found in many compounds with diverse biological effects. 1,2,4-Triazole derivatives could exert their antibacterial activity through inhibition of efflux pumps, filamentous temperature-sensitive protein Z, penicillin-binding protein, DNA gyrase, and topoisomerase IV, and they play an important role in the discovery of novel antibacterial agents. Among them, 1,2,4-triazole hybrids, which have the potential to exert dual/multiple mechanisms of action, possess a promising broad-spectrum antibacterial activity against a panel of clinically important drug-resistant pathogens including MRSA. This review outlines the recent developments of 1,2,4-triazole hybrids with a potential anti-MRSA activity, covering articles published between 2010 and 2020. The mechanisms of action, critical aspects of their design, and structure-activity relationships are also discussed.

Synthesis and Docking Study of N-(Cinnamoyl)-N'-(substituted)acryloyl Hydrazide Derivatives Containing Pyridinium Moieties as a Novel Class of Filamentous Temperature-Sensitive Protein Z Inhibitors against the Intractable Xanthomonas oryzae pv. oryzae Infections in Rice.

Xanthomonas oryzae pv. oryzae (Xoo) is an offensive phytopathogen that can invade a wide range of plant hosts to develop bacterial diseases, including the well-known rice bacterial leaf blight. However, few agrochemicals have been identified to effectively prevent and eliminate Xoo-induced diseases. Thus, designing novel antibacterial compounds on the basis of the potential targets from Xoo may lead to the discovery of highly efficient and innovative anti-Xoo agents. Filamentous temperature-sensitive protein Z (FtsZ), an important functional protein in the progression of cell division, has been widely reported and exploited as a target for creating antibacterial drugs in the field of medicine. Therefore, the fabrication of innovative frameworks targeting XooFtsZ may be an effective method for managing bacterial leaf blight diseases via blocking the binary division and reproduction of Xoo. As such, a series of novel N-(cinnamoyl)-N'-(substituted)acryloyl hydrazide derivatives containing pyridinium moieties were designed, and the anti-Xoo activity was determined. The bioassay results showed that compound A7 had excellent anti-Xoo activity (EC50 = 0.99 mg L-1) in vitro and distinct curative activity (63.2% at 200 mg L-1) in vivo. Further studies revealed that these designed compounds were XooFtsZ inhibitors, validating by the reduced GTPase activity of recombinant XooFtsZ, the nonfilamentous XooFtsZ assembly observed in the TEM images, and the prolonged Xoo cells from the fluorescence patterns. Computational docking studies showed that compound A7 had strong interactions with ASN34, GLN193, and GLN197 residues located in the α helix regions of XooFtsZ. The present study demonstrates the developed FtsZ inhibitors can serve as agents to control Xoo-induced infections.

Natural indole-containing alkaloids and their antibacterial activities.

As the growth in resistance to bacterial infection treatments poses a grave threat to global health in the 21st century, there is a constant need to explore novel antibacterial agents that have the ability to overcome drug resistance. Indole-containing alkaloids are widely distributed in nature, and a variety of indole-containing alkaloids have already been applied in clinical practice, proving that indole-containing alkaloids are fascinating and privileged scaffolds for the development of novel drugs. Moreover, indole-containing alkaloids could exert their antibacterial activity through the inhibition of efflux pumps, the biofilm, filamentous temperature-sensitive protein Z, and methicillin-resistant Staphylococcus aureus pyruvate kinase; so, indole-containing alkaloids constitute an important source of novel antibacterial agents. This review is an endeavor to highlight the advances in the development of indole-containing alkaloids with antibacterial potential, covering articles published in the recent 10 years.

New antimicrobial compounds produced by Seltsamia galinsogisoli sp. nov., isolated from Galinsoga parviflora as potential inhibitors of FtsZ

A total amount of 116 fungal strains, belonging to 30 genera, were acquired from the rhizosphere soil and plant of Galinsoga parviflora. A strain SYPF 7336, isolated from the rhizospheric soil, was identified as Seltsamia galinsogisoli sp. nov., by morphological and molecular analyses, which displayed high antibacterial activity. In order to study the secondary metabolites of Seltsamia galinsogisoli sp. nov., nine compounds were successfully seperated from the strain fermentation broth, including two new compounds and seven known compounds. Their structures were elucidated based on spectral analysis including 1D and 2D NMR. All the seperated compounds were evaluated for their antimicrobial activities. Compounds 2, 5 and 1 displayed antimicrobial activities against Staphylococcus aureus with MIC values of 25, 32 and 75 μg/mL, respectively. Moreover, morphological observation showed the coccoid cells of S. aureus to be swollen to a volume of 1.4 to 1.7-fold after treatment with compounds 1, 2 and 5, respectively. Molecular docking was carried out to investigate interactions of filamentous temperature-sensitive protein Z (FtsZ) with compounds 1, 2 and 5.

Cytotoxic and antimicrobial indole alkaloids from an endophytic fungus Chaetomium sp. SYP-F7950 of Panax notoginseng.

Two new compounds chetoseminudin F (1) and G (2) together with eleven known compounds were isolated from the solid fermentation products of the endophytic fungus Chaetomium sp. SYP-F7950. The structures of the isolated compounds were elucidated by extensive spectroscopic analyses, including 1D and 2D NMR, and HRFABMS experiments. The absolute configurations of chetoseminudin F (1) and G (2) were determined by comparing the electronic circular dichroism (ECD) spectrum with those of the reported references. A plausible biogenetic pathway for compounds 1–6 and 9–13 was proposed. These isolates were also evaluated for their antimicrobial and antitumor activity, revealing that chetoseminudin F (1) displayed more potent cytotoxicity against MDA-MB-231 cells with an IC50 value of 26.49 μmol L−1 more than the common chemotherapeutic agent (paclitaxel). In antimicrobial assay, compounds 6, 9, 11 and 12 had strong antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Enterococcus faecium and antifungal activity against Candida albicans with minimum inhibitory concentration (MIC) values ranging from 0.12 to 9.6 μg mL−1; meanwhile compounds 6, 8, 9 and 12 exhibited strong cytotoxicity with IC50 values of 2.75–8.68 μmol L−1 against tumor cell lines A549 and MDA-MB-231. In addition, morphological observation showed that treatment with compounds 6, 9 and 12 increased the mean length of B. subtilis by 1.6 to 1.8-fold. In silico molecular docking was applied to study the binding interactions between the compounds and the active sites of filamentous temperature-sensitive protein Z (FtsZ) from B. subtilis. Compounds 6, 9 and 12 displayed the low binding energies, strong H-bond interactions with FtsZ. On the basis of the antimicrobial activities, cellular phenotype observation and docking studies, compounds 6, 9 and 12 are considered to be a promising antimicrobial inhibitor of FtsZ.

New antimicrobial compounds produced by endophytic Penicillium janthinellum isolated from Panax notoginseng as potential inhibitors of FtsZ

A total of 180 fungal isolates, belonging to 20 genera and 47 species, were obtained from the roots, stems and leaves of Panax notoginseng. One isolate, the endophytic fungus Penicillium janthinellum SYPF 7899, displayed the strongest antibacterial activity and was studied for its production of secondary metabolites. In total, three new compounds, including rotational isomers 1a, 1b and 2 were isolated from the solid cultures of P. janthinellum, as well as eight known compounds (3−10). These structures were determined on the basis of 1D, 2D NMR and electronic circular dichroism (ECD) spectroscopic analyses as well as theoretical calculations. Compound 1 exhibited significant inhibitory activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 15 and 18 μg/ml, respectively. The other compounds showed moderate or weak activities. In addition, morphological observation showed the rod-shaped cells of B. subtilis growing into long filaments, which reached 1.5- to 2-fold of the length of the original cells after treatment with compound 1. The coccoid cells of S. aureus exhibited a similar response and swelled to a 2-fold volume after treatment with compound 1. In silico molecular docking was explored to study the binding interactions between the compounds and the active sites of filamentous temperature-sensitive protein Z (FtsZ) from B. subtilis and S. aureus. Compound 1a, 1b and 2 showed high binding energies, strong H-bond interactions and hydrophobic interactions with FtsZ. Based on the antimicrobial activities, cellular phenotype observation and docking studies, compound 1 is considered to be a promising antimicrobial inhibitor of FtsZ.

An endophytic Fungi of Ginkgo biloba L. produces antimicrobial metabolites as potential inhibitors of FtsZ of Staphylococcus aureus

A total of 58 fungal isolates, belonging to 24 genera, were obtained from the leaves, stems and roots of Ginkgo biloba L.. Among them, one endophytic fungal strain, Penicillium cataractum SYPF 7131, displayed the strongest antibacterial activity. Four new compounds (1–4) were isolated from the strain fermentation broth together with four known compounds (5–8). These structures were determined on the basis of 1D and 2D NMR and [Rh2(OCOCF3)4]-induced electronic circular dichroism (ECD) spectroscopic analyses. All the isolated compounds were screened for their in vitro antimicrobial activities. Compound 3 and 4 showed moderate inhibitory activity against Staphylococcus aureus. Compound 7 exhibited significant inhibitory activity against S. aureus with MIC value of 10 μg/mL. Further, the in silico molecular docking studies of the active compounds was used to explore the binding interactions with the active site of filamentous temperature-sensitive protein Z (FtsZ) from Staphylococcus aureus. The docking results revealed that compounds 3, 4 and 7 showed high binding energies, strong H-bond interactions and hydrophobic interactions with FtsZ from S. aureus validating the observed antimicrobial activity. Based on antimicrobial activities and docking studies, compounds 3, 4 and 7 were identified as promising antimicrobial lead molecules.

Identification of TB-E12 as a novel FtsZ inhibitor with anti-tuberculosis activity

The global pandemic of multidrug-resistant (MDR) Mycobacterium tuberculosis (TB) drives for more effective anti-TB drugs with new drug target. Filamentous temperature sensitive protein Z (FtsZ), a GTP dependent prokaryotic cell division protein, forms a dynamic Z-ring in the center of the cell. Differences between bacterial FtsZ and eukaryotic tubulin make FtsZ a highly attractive drug target. In this study, we used phenotype screening of M. smegmatis and model screening targeting M. tuberculosis FtsZ (Mtb-FtsZ) to identify a hit compound TB-E12. TB-E12 was found to prevent the growth of M. smegmatis by inhibiting the GTPase activity of Mtb-FtsZ. Molecular docking and site-directed mutagenesis analyses identified Asn22 of Mtb-FtsZ as the key amino site. The higher MIC of TB-E12 for M. smegmatis strain overexpressing Mtb-FtsZ confirmed that Mtb-FtsZ is likely the target. Importantly, TB-E12 exhibits excellent anti-TB activity, but had no anti-bacterial activity to other strains. In vitro, the proliferation of Mycobacterium smegmatis was inhibited by TB-E12. All these results indicate TB-E12 is a promising lead compound against drug-resistant tuberculosis.

Structural insights of Staphylococcus aureus FtsZ inhibitors through molecular docking, 3D-QSAR and molecular dynamics simulations

Filamentous temperature-sensitive protein Z (FtsZ) is a protein encoded by the FtsZ gene that assembles into a Z-ring at the future site of the septum of bacterial cell division. Structurally, FtsZ is a homolog of eukaryotic tubulin but has low sequence similarity; this makes it possible to obtain FtsZ inhibitors without affecting the eukaryotic cell division. Computational studies were performed on a series of substituted 3-arylalkoxybenzamide derivatives reported as inhibitors of FtsZ activity in Staphylococcus aureus. Quantitative structure-activity relationship models (QSAR) models generated showed good statistical reliability, which is evident from r2ncv and r2loo values. The predictive ability of these models was determined and an acceptable predictive correlation (r2Pred) values were obtained. Finally, we performed molecular dynamics simulations in order to examine the stability of protein-ligand interactions. This facilitated us to compare free binding energies of cocrystal ligand and newly designed molecule B1. The good concordance between the docking results and comparative molecular field analysis (CoMFA)/comparative molecular similarity indices analysis (CoMSIA) contour maps afforded obliging clues for the rational modification of molecules to design more potent FtsZ inhibitors.