Targeting Outer Membrane Protein Component AdeC for the Discovery of Efflux Pump Inhibitor against AdeABC Efflux Pump of Multidrug Resistant Acinetobacter baumannii

Investigation of Peptidoglycan-Associated Lipoprotein of Acinetobacter baumannii and Its Interaction with Fibronectin To Find Its Therapeutic Potential

Acinetobacter baumannii causes hospital-acquired infections and is responsible for high mortality and morbidity. The interaction of this bacterium with the host is critical in bacterial pathogenesis and infection. Here, we report the interaction of peptidoglycan-associated lipoprotein (PAL) of A. baumannii with host fibronectin (FN) to find its therapeutic potential. The proteome of A. baumannii was explored in the host-pathogen interaction database to filter out the PAL of the bacterial outer membrane that interacts with the host's FN protein. This interaction was confirmed experimentally using purified recombinant PAL and pure FN protein. To investigate the pleiotropic role of PAL protein, different biochemical assays using wild-type PAL and PAL mutants were performed. The result showed that PAL mediates bacterial pathogenesis, adherence, and invasion in host pulmonary epithelial cells and has a role in the biofilm formation, bacterial motility, and membrane integrity of bacteria. All of the results suggest that PAL's interaction with FN plays a vital role in host-cell interaction. In addition, the PAL protein also interacts with Toll-like receptor 2 and MARCO receptor, which suggests the role of PAL protein in innate immune responses. We have also investigated the therapeutic potential of this protein for vaccine and therapeutic design. Using reverse vaccinology, PAL's potential epitopes were filtered out that exhibit binding potential with host major histocompatibility complex class I (MHC-I), MHC-II, and B cells, suggesting that PAL protein is a potential vaccine target. The immune simulation showed that PAL protein could elevate innate and adaptive immune response with the generation of memory cells and would have subsequent potential to eliminate bacterial infection. Therefore, the present study highlights the interaction ability of a novel host-pathogen interacting partner (PAL-FN) and uncovers its therapeutic potential to combat infection caused by A. baumannii.

Resistance mechanisms of tigecycline in Acinetobacter baumannii

Acinetobacter baumannii is widely distributed in nature and in hospital settings and is a common pathogen causing various infectious diseases. Currently, the drug resistance rate of A. baumannii has been persistently high, showing a worryingly high resistance rate to various antibiotics commonly used in clinical practice, which greatly limits antibiotic treatment options. Tigecycline and polymyxins show rapid and effective bactericidal activity against CRAB, and they are both widely considered to be the last clinical line of defense against multidrug resistant A. baumannii. This review focuses with interest on the mechanisms of tigecycline resistance in A. baumannii. With the explosive increase in the incidence of tigecycline-resistant A. baumannii, controlling and treating such resistance events has been considered a global challenge. Accordingly, there is a need to systematically investigate the mechanisms of tigecycline resistance in A. baumannii. Currently, the resistance mechanism of A. baumannii to tigecycline is complex and not completely clear. This article reviews the proposed resistance mechanisms of A. baumannii to tigecycline, with a view to providing references for the rational clinical application of tigecycline and the development of new candidate antibiotics.

Tripartite efflux pumps of the RND superfamily: what did we learn from computational studies?

Bacterial resistance to antibiotics has been long recognized as a priority to address for human health. Among all micro-organisms, the so-called multi-drug resistant (MDR) bacteria, which are resistant to most, if not all drugs in our current arsenal, are particularly worrisome. The World Health Organization has prioritized the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) pathogens, which include four Gram-negative bacterial species. In these bacteria, active extrusion of antimicrobial compounds out of the cell by means of 'molecular guns' known as efflux pumps is a main determinant of MDR phenotypes. The resistance-nodulation-cell division (RND) superfamily of efflux pumps connecting the inner and outer membrane in Gram-negative bacteria is crucial to the onset of MDR and virulence, as well as biofilm formation. Thus, understanding the molecular basis of the interaction of antibiotics and inhibitors with these pumps is key to the design of more effective therapeutics. With the aim to contribute to this challenge, and complement and inspire experimental research, in silico studies on RND efflux pumps have flourished in recent decades. Here, we review a selection of such investigations addressing the main determinants behind the polyspecificity of these pumps, the mechanisms of substrate recognition, transport and inhibition, as well as the relevance of their assembly for proper functioning, and the role of protein-lipid interactions. The journey will end with a perspective on the role of computer simulations in addressing the challenges posed by these beautifully complex machineries and in supporting the fight against the spread of MDR bacteria.

Assessment of potassium ion channel during electric signalling in biofilm formation of Acinetobacter baumannii for finding antibiofilm molecule

Acinetobacter baumannii is an opportunistic ESKAPE pathogen which causes nosocomial infections and can produce biofilms that act as resistant determinants. The role of quorum sensing (chemical signaling) in biofilm establishment has already been studied extensively, but the existence of electrochemical signaling during biofilm formation by A. baumannii has not yet been investigated. The current study evaluated the presence of electrical signaling, types of ion channels involved, and their role in biofilm formation using spectroscopic and microbiological methods. The findings suggest that the potassium ion channel has a significant role in the electrical signaling during the biofilm formation by A. baumannii. Further, in-silico screening, molecular mechanics, and molecular dynamic simulation studies identify a potential lead, ZINC12496555(a specific inhibitor), which targets the potassium ion channel protein of A. baumannii. Mutational analysis of the interacting residues showed alterations in the unfolding rate of this protein after the selected mutation, which shows its role in the stability of this protein. It was also observed that identified lead has high antibiofilm activity, no human off-targets, and non-cytotoxicity to cell lines. Thus, identified lead against the potassium channel of A baumannii may be used as an effective therapeutic for the treatment of A. baumannii infections after further experimental validation.

A subtractive proteomics approach for the identification of immunodominant Acinetobacter baumannii vaccine candidate proteins

Background

Acinetobacter baumannii is one of the most life-threatening multidrug-resistant pathogens worldwide. Currently, 50%–70% of clinical isolates of A. baumannii are extensively drug-resistant, and available antibiotic options against A. baumannii infections are limited. There is still a need to discover specific de facto bacterial antigenic proteins that could be effective vaccine candidates in human infection. With the growth of research in recent years, several candidate molecules have been identified for vaccine development. So far, no public health authorities have approved vaccines against A. baumannii.

Methods

This study aimed to identify immunodominant vaccine candidate proteins that can be immunoprecipitated specifically with patients’ IgGs, relying on the hypothesis that the infected person’s IgGs can capture immunodominant bacterial proteins. Herein, the outer-membrane and secreted proteins of sensitive and drug-resistant A. baumannii were captured using IgGs obtained from patient and healthy control sera and identified by Liquid Chromatography- Tandem Mass Spectrometry (LC-MS/MS) analysis.

Results

Using the subtractive proteomic approach, we determined 34 unique proteins captured only in drug-resistant A. baumannii strain via patient sera. After extensively evaluating the predicted epitope regions, solubility, transverse membrane characteristics, and structural properties, we selected several notable vaccine candidates.

Conclusion

We identified vaccine candidate proteins that triggered a de facto response of the human immune system against the antibiotic-resistant A. baumannii. Precipitation of bacterial proteins via patient immunoglobulins was a novel approach to identifying the proteins that could trigger a response in the patient immune system.

Targeting and ultrabroad insight into molecular basis of Resistance-nodulation-cell division efflux pumps

Resistance-nodulation-cell devision (RND) efflux pump variants have attracted a great deal of attention for efflux of many antibiotic classes, which leads to multidrug-resistant bacteria. The present study aimed to discover the interaction between the RND efflux pumps and antibiotics, find the conserved and hot spot residues, and use this information to target the most frequent RND efflux pumps. Protein sequence and 3D conformational alignments, pharmacophore modeling, molecular docking, and molecular dynamics simulation were used in the first level for discovering the function of the residues in interaction with antibiotics. In the second level, pharmacophore-based screening, structural-based screening, multistep docking, GRID MIF, pharmacokinetic modeling, fragment molecular orbital, and MD simulation were utilized alongside the former level information to find the most proper inhibitors. Five conserved residues, containing Ala209, Tyr404, Leu415, Asp416, and Ala417, as well as their counterparts in other OMPs were evaluated as the crucial conserved residues. MD simulation confirmed that a number of these residues had a key role in the performance of the efflux antibiotics; therefore, some of them were hot spot residues. Fourteen ligands were selected, four of which interacted with all the crucial conserved residues. NPC100251 was the fittest OMP inhibitor after pharmacokinetic computations. The second-level MD simulation and FMO supported the efficacy of the NPC100251. It was exhibited that perhaps OMPs worked as the intelligent and programable protein. NPC100251 was the strongest OMPs inhibitor, and may be a potential therapeutic candidate for MDR infections.

Identification of Promoter Region Markers Associated With Altered Expression of Resistance-Nodulation-Division Antibiotic Efflux Pumps in Acinetobacter baumannii

Genetic alterations leading to the constitutive upregulation of specific efflux pumps contribute to antibacterial resistance in multidrug resistant bacteria. The identification of such resistance markers remains one of the most challenging tasks of genome-level resistance predictors. In this study, 487 non-redundant genetic events were identified in upstream zones of three operons coding for resistance-nodulation-division (RND) efflux pumps of 4,130 Acinetobacter baumannii isolates. These events included insertion sequences, small indels, and single nucleotide polymorphisms. In some cases, alterations explicitly modified the expression motifs described for these operons, such as the promoter boxes, operators, and Shine-Dalgarno sequences. In addition, changes in DNA curvature and mRNA secondary structures, which are structural elements that regulate expression, were also calculated. According to their influence on RND upregulation, the catalog of upstream modifications were associated with “experimentally verified,” “presumed,” and “probably irrelevant” degrees of certainty. For experimental verification, DNA of upstream sequences independently carrying selected markers, three for each RND operon, were fused to a luciferase reporter plasmid system. Five out of the nine selected markers tested showed significant increases in expression with respect to the wild-type sequence control. In particular, a 25-fold expression increase was observed with the ISAba1 insertion sequence upstream the adeABC pump. Next, overexpression of each of the three multi-specific RND pumps was linked to their respective antibacterial substrates by a deep A. baumannii literature screen. Consequently, a data flow framework was then developed to link genomic upregulatory RND determinants to potential antibiotic resistance. Assignment of potential increases in minimal inhibitory concentrations at the “experimentally verified” level was permitted for 42 isolates to 7–8 unrelated antibacterial agents including tigecycline, which is overlooked by conventional resistome predictors. Thus, our protocol may represent a time-saving filter step prior to laborious confirmation experiments for efflux-driven resistance. Altogether, a computational-experimental pipeline containing all components required for identifying the upstream regulatory resistome is proposed. This schema may provide the foundational stone for the elaboration of tools approaching antibiotic efflux that complement routine resistome predictors for preventing antimicrobial therapy failure against difficult-to-threat bacteria.

An Evolutionary Conservation and Druggability Analysis of Enzymes Belonging to the Bacterial Shikimate Pathway

Enzymes belonging to the shikimate pathway have long been considered promising targets for antibacterial drugs because they have no counterpart in mammals and are essential for bacterial growth and virulence. However, despite decades of research, there are currently no clinically relevant antibacterial drugs targeting any of these enzymes, and there are legitimate concerns about whether they are sufficiently druggable, i.e., whether they can be adequately modulated by small and potent drug-like molecules. In the present work, in silico analyses combining evolutionary conservation and druggability are performed to determine whether these enzymes are candidates for broad-spectrum antibacterial therapy. The results presented here indicate that the substrate-binding sites of most enzymes in this pathway are suitable drug targets because of their reasonable conservation and druggability scores. An exception was the substrate-binding site of 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase, which was found to be undruggable because of its high content of charged residues and extremely high overall polarity. Although the presented study was designed from the perspective of broad-spectrum antibacterial drug development, this workflow can be readily applied to any antimicrobial target analysis, whether narrow- or broad-spectrum. Moreover, this research also contributes to a deeper understanding of these enzymes and provides valuable insights into their properties.

Design of novel hybrid secondary metabolite targets to diguanylate cyclase of Acinetobacter baumannii

Biofilm formation in bacteria is a resistance determinant and is positively regulated by cyclic diguanylate signaling. This signaling is a near universal signaling, and c-di-GMP produced by diguanylate cyclase (DGC) in this signaling is involved in different bacterial behaviors. The present study aims to find a plant-based novel hybrid therapeutic agent that can target the DGC of Acinetobacter baumannii. In this study, we have tried to design a hybrid molecule from the anti-biofilm plant secondary metabolites and screened its binding with the DGC of A. baumannii. The modeled and validated DGC was used to identify the active site and docking grid. Designed hybrid compounds were analysed for their interaction with the active site residues of DGC of A. baumannii. Further, the binding free energies of the docked complexes obtained from the Generalized Born model and Solvent Accessibility (MMGBSA) were analysed. The results indicated that VR-QEg-180 has a predicted high binding affinity with enzyme DGC as compared to other hybrids, parent secondary metabolites and positive control. Molecular dynamics simulation (MDS) analysis confirmed the interaction of VR-QEg-180 with DGC of the A. baumannii. The designed lead has favorable ADMET properties, has no human off-targets and has no predicted cytotoxicity in cell lines. Therefore, the designed hybrid molecule (VR-QEg-180) targeting the DGC of A. baumannii may play a very significant role in controlling this pathogen.

In Silico Approach for Phytocompound-Based Drug Designing to Fight Efflux Pump-Mediated Multidrug-Resistant Mycobacterium tuberculosis

Tuberculosis (TB), caused by the bacteria Mycobacterium tuberculosis, is one of the principal causes of death in the world despite the existence of a significant number of antibiotics aimed against it. This is mainly due to the drug resistance mechanisms present in the bacterium, which leads to multidrug-resistant tuberculosis (MDR-TB). Additionally, the development of new antibiotics has become limited over the years. Although there are various drug resistance mechanisms present, efflux pumps are of utmost importance because they extrude out several dissimilar antitubercular drugs out of the cell. There are many efflux pump proteins present in Mycobacterium tuberculosis. Therefore, blocking these efflux pumps by inhibitors can raise the efficacy of the existing antibiotics and may also pave the path for the discovery and synthesis of new drugs. Plant compounds can act as a resource for the development of efflux pump inhibitors (EPIs), which may eventually replace or augment the current therapeutic options. This is mainly because plants have been traditionally used for ages for food or treatment and are considered safe with little or no side effects. Various computational tools are available which are used for the virtual screening of a large number of phytocompounds within a short span of time. This review aims to highlight the mechanism and appearance of drug resistance in Mycobacterium tuberculosis with emphasis on efflux pumps along with the significance of phytochemicals as inhibitors of these pumps and their screening strategy by computational approaches.

Denovo designing, retro-combinatorial synthesis, and molecular dynamics analysis identify novel antiviral VTRM1.1 against RNA-dependent RNA polymerase of SARS CoV2 virus

A novel coronavirus disease (COVID-19) caused by SARS-CoV2 has now spread globally. Replication/transcription machinery of this virus consists of RNA-dependent RNA polymerase (nsp12 or RdRp) and its two cofactors nsp7 and nsp8 proteins. Hence, RdRp has emerged as a promising target to control COVID-19. In the present study, we are reporting a novel inhibitor VTRM1.1 against the RdRp protein of SARS CoV2. A series of antivirals were tested for binding to the catalytic residues of the active site of RdRp protein. In-silico screening, molecular mechanics, molecular dynamics simulation (MDS) analysis suggest ribavirin, and remdesivir have good interaction with the binding site of the RdRp protein as compared to other antiviral investigated. Hence, ribavirin and remdesivir were used for the denovo fragments based antiviral design. This design, along with docking and MDS analysis, identified a novel inhibitor VTRM1 that has better interaction with RdRp as compared to their parent molecules. Further, to produce a lead-like compound, retrosynthetic analysis, and combinatorial synthesis were performed, which produces 1000 analogs of VTRM1. These analogs were analysed by docking and MDS analysis that identified VTRM1.1 as a possible lead to inhibit RdRp protein. This lead has a good docking score, favourable binding energy and bind at catalytic residues of the active site of RdRp. The VTRM1.1 also interacts with RdRp in the presence of RNA primer and other cofactors. It was also seen that, VTRM1.1 do not have off-target in human. Therefore, the present study suggests a hybrid inhibitor VTRM1.1 for the RNA-dependent RNA polymerase of SARS CoV2 that may be useful to control infection caused by COVID-19.

De novo design, retrosynthetic analysis and combinatorial synthesis of a hybrid antiviral (VTAR-01) to inhibit the interaction of SARS-CoV2 spike glycoprotein with human angiotensin-converting enzyme 2

SARS-like coronavirus (SARS-CoV2) has emerged as a global threat to humankind and is rapidly spreading. The infectivity, pathogenesis and infection of this virus are dependent on the interaction of SARS-CoV2 spike protein with human angiotensin converting enzyme 2 (hACE2). Spike protein contains a receptor-binding domain (RBD) that recognizes hACE-2. In the present study, we are reporting a de novo designed novel hybrid antiviral ‘VTAR-01’ molecule that binds at the interface of RBD-hACE2 interaction. A series of antiviral molecules were tested for binding at the interface of RBD-hACE2 interaction. In silico screening, molecular mechanics and molecular dynamics simulation (MDS) analysis suggest ribavirin, ascorbate, lopinavir and hydroxychloroquine have strong interaction at the RBD-hACE2 interface. These four molecules were used for de novo fragment-based antiviral design. De novo designing, docking and MDS analysis identified a ‘VTAR’ hybrid molecule that has better interaction with this interface than all of the antivirals used to design it. We have further used retrosynthetic analysis and combinatorial synthesis to design 100 variants of VTAR molecules. Retrosynthetic analysis and combinatorial synthesis, along with docking and MDS, identified that VTAR-01 interacts with the interface of the RBD-ACE2 complex. MDS analysis confirmed its interaction with the RBD-ACE2 interface by involving Glu35 and Lys353 of ACE2, as well as Gln493 and Ser494 of RBD. Interaction of spike protein with ACE2 is essential for pathogenesis and infection of this virus; hence, this in silico designed hybrid antiviral molecule (VTAR-01) that binds at the interface of RBD-hACE2 may be further developed to control the infection of SARS-CoV2.

Summary: SARS-CoV2 has caused an outbreak globally and is responsible for high mortality and morbidity. Interaction of the receptor-binding domain of spike protein of this virus with human angiotensin converting enzyme (ACE2) is vital for the infection. Hence, a de novo designed hybrid antiviral molecule (VTAR-01) targeting RBD-ACE2 interaction may play a very significant role in controlling the COVID-19 disease.

Novel hybrid antiviral VTRRT-13V2.1 against SARS-CoV2 main protease: retro-combinatorial synthesis and molecular dynamics analysis

The COVID-19 pandemic caused by SARS-CoV-2 has now emerged as a global health problem and is responsible for high mortality and morbidity. The SARS-CoV-2 main protease (M^pro) emerged as a promising drug target because of its essential role in the processing of polyproteins, which is translated from viral RNA. The present study reports a designed novel hybrid antiviral molecule (VTRRT-13.V2.1) against SARS-CoV2 main protease. A series of different combinations of hybrid antiviral were generated from nonspecific antiviral molecules currently used to control COVID-19. To enhance the specificity of the designed hybrid antiviral molecule, the core pocket region of the active site of M^pro protein was targeted. In-silico screening, molecular mechanics, molecular dynamics simulation (MDS) analysis identified a hybrid VTRRT-13.V2 molecule. Retrosynthetic analysis and combinatorial synthesis generated 1000 analogs of VTRRT-13.V2 molecules. Docking, molecular mechanics, and MDS analysis selected VTRRT-13.V2.1 as a possible inhibitor for SARS-CoV2 main protease. Comparative analysis of all the results showed that VTRRT-13.V2.1 have the highest docking Glide score (-12.28 kcal/mol) and best binding energy (-52.23 kcal/mol) as compared to the other hybrid constructs such as VTRRT-13.V2 (-9.47 and -47.36 kcal/mol), VTRRT-13 (-8.9 and -47.55 kcal/mol), and current antiviral investigated. The mutational sensitivity screening showed that binding residues of M^pro are not present in mutation hotspots. It was also observed that VTRRT-13.V2.1 does not have any human off-targets. SARS-CoV2 main protease is essential for the survival of this virus; hence, a designed novel hybrid antiviral molecule (VTRRT-13.V2.1) might be useful to control the infection of COVID-19 infection.

Rational targeting of Wzb phosphatase and Wzc kinase interaction inhibits extracellular polysaccharides synthesis and biofilm formation in Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic nosocomial pathogen, and responsible for high mortality and morbidity. Biofilm formation is one of the resistance determinants, where extracellular polysaccharide (EPS) is an essential component. EPS synthesis and its export is regulated by the bacterial Wza-Wzb-Wzc system. Wzc exhibits auto-phosphorylation protein tyrosine kinase activity, while Wzb is a protein tyrosine phosphatase. Wzb mediates dephosphorylation of Wzc. Dephosphorylated Wzc is required for the export of the EPS through porin Wza-Wzc complex. It shows that the interaction of Wzb with Wzc is critical for the export of EPS. Therefore, if the Wzb-Wzc interaction is inhibited, then it might hinder the EPS transport and diminish the biofilm formation. In this study, we have modelled the Wzb, and Wzc proteins and further validated using PSVS, ProSA, RAMPAGE, and PDBsum. The modelled proteins were used for protein-protein docking. The docked protein-protein complex was minimized by Schrodinger software using OPLS_2005 force field. The binding site of the minimized Wzb-Wzc complex was identified by Sitemap. The high throughput virtual screening identified Labetalol hydrochloride and 4-{1-hydroxy-2-[(1-methyl-3-phenylpropyl) amino] propyl} phenol from FDA-approved drug library based on their interaction at the interface of Wzb-Wzc complex. The inhibitor-protein complex was further undergone molecular mechanics analysis using Generalized Born model and Solvent Accessibility (MMGBSA) to estimate the binding free energies. The lead was also used to generate the pharmacophore model and screening the molecule with antimicrobial scaffold. The identified lead was experimentally validated for its effect on EPS quantity and biofilm formation by A. baumannii. Wzb-Wzc interaction is essential for biofilm and EPS export; hence, the identified lead might be useful to regulate the biofilm formation by A. baumannii.

Prioritization of potential vaccine targets using comparative proteomics and designing of the chimeric multi-epitope vaccine against Pseudomonas aeruginosa

Multidrug-resistant Pseudomonas aeruginosa is one of the worldwide health problems involved in elevated mortality and morbidity. Therefore, it is important to find a therapeutic for this pathogen. In the present study, we have designed a chimeric vaccine against P. aeruginosa with the help of comparative proteomics and reverse vaccinology approaches. Using comparative subtractive proteomic analysis of 1,191 proteomes of P. aeruginosa, a total of twenty unique non-redundant proteomes were selected. In these proteomes, fifteen outer membrane proteins (OMPs) of P. aeruginosa were selected based on the basis of hydrophilicity, non-secretory nature, low transmembrane helix (<1), essentiality, virulence, pathway association, antigenic, and protein-protein network analysis. Reverse vaccinology approach was used to identify antigenic and immunogenic MHC class I, MHC class II and B cell epitopes present in the selected OMPs that can enhance T cell and B cell mediated immunogenicity. The selected epitopes were shortlisted based on their allergenicity, toxicity potentials, solubility, and hydrophilicity analysis. Immunogenic peptides were used to design a multi-epitope vaccine construct. Immune-modulating adjuvants and PADRE (Pan HLA-DR epitopes) sequence were added with epitopes sequence to enhance the immunogenicity. All the epitopes, adjuvants and PADRE sequence were joined by linkers. The designed vaccine constructs (VT1, VT2, VT3, and VT4) were analyzed by their physiochemical properties using different tools. Selected chimeric vaccine constructs (VT1, VT3, and VT4) were further shortlisted by their docking score with different HLA alleles. The final selected VT4 construct was docked with TLR4/MD2 complex and confirmed by molecular dynamics simulation studies. The final vaccine VT-4 construct was in-silico cloned in pET28a. Therefore, the designed construct VT4 may be studied to control the interaction of P. aeruginosa with host and infection caused by P. aeruginosa.

Molecular insight into the therapeutic potential of phytoconstituents targeting protein conformation and their expression

BACKGROUND

Native protein conformation is essential for the functional activity of the proteins and enzymes. Defects in conformation or alterations in expression of the proteins have been reported in various diseases.

PURPOSE

The aim of this study is to review the molecular insight into the therapeutic potential of phytoconstituents targeting protein conformations or expressions.

METHODS

Published literatures were searched in PubMed, Scopus, Web of Science; Article published till Dec 2017 were extracted. The literature was assessed from the Central University of Rajasthan, India. Present study evaluate article based on the role of active plant constituents on the conformation and expression of the different proteins.

RESULTS

Plant components play their role either at the molecular level or cellular level and exhibit antibacterial, antiviral, anti-neurodegenerative and other activities. Plant active compounds isolated from different plants may either stabilize or destabilize the conformation of proteins or alter expression level of the protein involved in these diseases, therefore, can play a significant role in preventing diseases caused by the alteration in these proteins.

CONCLUSION

In the present article, we have reviewed the molecular mechanism of plant active compounds, their target proteins, methods of extraction and identification, and their biological significances. Therefore, a proper understanding of the effect of these herbal molecules on the concerned proteins may help to develop new herbal-based therapeutics for various diseases.

Post-translational modification of ESKAPE pathogens as a potential target in drug discovery

ESKAPE pathogens are gaining clinical importance owing to their high pervasiveness and increasing resistance to various antimicrobials. These bacteria have several post-translational modifications (PTMs) that destabilize or divert host cell pathways. Prevalent PTMs of ESKAPE pathogens include addition of chemical groups (acetylation, phosphorylation, methylation and hydroxylation) or complex molecules (AMPylation, ADP-ribosylation, glycosylation and isoprenylation), covalently linked small proteins [ubiquitylation, ubiquitin-like proteins (UBL) conjugation and small ubiquitin-like modifier (SUMO)] or modification of amino acid side-chains (eliminylation and deamidation). Therefore, the understanding of different bacterial PTMs and host proteins manipulated by these PTMs provides better insight into host-pathogen interaction and will also help to develop new antibacterial agents against ESKAPE pathogens.