Binding interaction of laccases from Bacillus Subtilis after industrial dyes exposure: Molecular docking and molecular dynamics simulation studies

Dyes are becoming more widely used around the world wide, but there is no effective bioremediation approach for removing them completely from the environment. Several dyes are mentioned to be degraded through bacteria; however, it's still unknown how the particular enzymes act throughout the dye degradation. The behavior and function of these enzymes in the biodegradation of azo dyes (Textile dyes) had been investigated experimentally by the numbers of the researchers, however, the molecular mechanisms remain unclear. Therefore, the interaction mechanisms of textile dye (methyl orange) with laccase from B. subtilis were explored through molecular docking and molecular dynamics simulations, the three selected dyes (methyl orange, malachite green, and acid blue 62) that interact positively with laccase on the basis of their maximum binding energy, molecular docking results indicate that one of the three dyes is more stable as a target for degradation through Bacillus subtilis laccase. Therefore, subsequent research focused solely on one substrate: methyl orange. Molecular Dynamics simulation study was applied after the molecular docking to determine the interaction between laccases and methyl orange dyes. The trajectory was proved with root mean square deviation and root mean square fluctuation analysis. According to the molecular dynamics simulation results, laccase-methyl orange complexes remain stable during the catalytic reaction. So, this study demonstrates how laccase is involved in methyl orange bioremediation.

Modelamiento in silica de la liasa organomercurial (MerB) de Pseudamanas fluarescens / In silico modeling of Pseudomonas fluoresceins organomercurial lyase (MerB) / Modelagem in silica da liase organomercurial (MerB) de Pseudamanas fluarescens

Resumen El modelamiento ¡n silíco ha sido de gran contribución en los procesos proteómicos, desarrollando estructuras de las secuencias proteicas ya existentes, que por motivos de altos costos y las diferentes tecnologías necesarias para el desarrollo de estas metodologías, se encuentran deficientes en el número de modelamientos de proteínas disponibles. Entre aquellas secuencias con carencia de estructura proteica se encuentra la proteína liasa organomercurial (MerB) de Pseudomonas /luorescens, importante en la resistencia al mercurio. En el presente artículo se analizó tanto estructural como funcionalmente la proteína MerB en Pseudomonas jluorescens, utilizando la herramienta de la química estructural "modelamiento por homología" mediante plataformas bioinformáticas, con el fin de obtener un modelo que represente la estructura 3D más precisa y que capturen las mejores variantes estructurales entre todas las posibles conformaciones de las proteínas en la familia. En este trabajo, se desarrolló un método comparativo de la secuencia estudiada con las reportadas en las bases de datos para las proteínas MerB del género Pseudomonas. Se propone un modelo tridimensional para la enzima (MerB) en P. jluorescens, mediante el modelamiento por homología, se muestra la caracterización en la estructura secundaria, terciaria, la caracterización del dominio catalítico y los motivos estructurales presentes.

Abstract In silico modeling has made a great contribution to proteomic processes, developing structures of the already existing protein sequences, which for reasons of high costs and the different technologies necessary for the development of these methodologies, are deficient in the number of models of available proteins. Among those sequences lacking protein structure is the organomercurial lyase (MerB) protein from Pseudomonas fluoresceins, important in mercury resistance. In this article, the MerB protein in Pseudomonas fluorescens was analyzed both structurally and functionally, using the structural chemistry tool "homology modeling" using bioinformatic platforms, in order to obtain a model that represents the most accurate 3D structure and that captures the best structural variants among all the possible conformations of the proteins in the family. In this work, a comparative method of the sequence studied with those reported in the databases for MerB proteins of the genus Pseudomonas was developed. A three-dimensional model for the enzyme (MerB) in P. fluorescens is proposed, through homology modeling, the characterization at the secondary and tertiary structure level, the characterization of the catalytic domain and the structural motifs present is shown.

Resumo A modelagem in silico tem dado um grande contributo para os processos proteómicos, desenvolvendo estruturas de sequências de proteínas já existentes, as quais, pelos elevados custos e pelas diferentes tecnologias necessárias ao desenvolvimento destas metodologias, são deficientes no número de modelos de proteínas disponíveis. Entre as sequências sem estrutura protéica está a proteína organomercurial liase (MerB) de Pseudomonas fluorescens, importante na resistência ao mercúrio. Neste artigo, a proteína MerB em Pseudomonas fluorescens foi analisada estrutural e funcionalmente, usando a ferramenta de química estrutural "modelagem de homologia" usando plataformas de bioinformática, a fim de obter um modelo que represente a estrutura 3D mais precisa e que capture as melhores variantes estruturais. entre todas as conformações possíveis das proteínas da família. Neste trabalho, foi desenvolvido um método comparativo da sequência estudada com aqueles relatados em bancos de dados para proteínas MerB do gênero Pseudomonas. Um modelo tridimensional para a enzima (MerB) em P. fluorescens é proposto, através de modelagem por homologia, a caracterização em nível de estrutura secundária e terciária, a caracterização do domínio catalítico e os motivos estruturais presentes são mostradas.

In silico study to predict promiscuous T cell and B cell-epitopes derived from the vaccine candidate antigens of Plasmodium vivax binding to MHC class-II alleles

Malaria is one of the major causes of health and disability globally, even after tremendous efforts to eradicate it. Till date no highly effective vaccine is available for its control. The primary reason for the low efficacy of vaccines is extensive polymorphism in potential vaccine candidate antigen genes and HLA polymorphisms in the human population. This problem can be resolved by developing a vaccine using promiscuous peptides to combine the number of HLA alleles. This study predicted T and B cell epitopes (promiscuous peptides) by targeting PPPK-DHPS and DHFR-TS proteins of Plasmodium vivax, using different in silico tools. Selected peptides were characterized as promiscuous peptides on the basis of their immunogenicity, antigenicity and hydrophobicity. Furthermore, to confirm their immunogenicity, these peptides were utilized for molecular modelling and docking analysis. For determining the requisite affinity with distinct HLA Class-I, and HLA Class-II alleles, only five peptides for DHFR-TS and 3 peptides for PPPK-DHPS were chosen as promiscuous peptides. The D1 peptide has the maximum binding energy with HLA alleles, according to HLA-peptide complex modelling and binding interaction analyses. These findings could lead to the development of epitope-based vaccinations with improved safety and efficacy. These epitopes could be major vaccine targets in P. vivax as they possess a higher number of promiscuous peptides. Also, the B cell epitopes possess maximum affinity towards different alleles as analyzed by docking scores. However, further investigation is warranted in vitro and in vivo.

Structural basis of SARS-CoV-23CLpro and anti-COVID-19 drug discovery from medicinal plants / 药物分析学报

The recent pandemic of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has raised global health concerns. The viral 3-chymotrypsin-like cysteine protease (3CLpro) enzyme controls coronavirus replication and is essential for its life cycle. 3CLpro is a proven drug discovery target in the case of severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). Recent studies revealed that the genome sequence of SARS-CoV-2 is very similar to that of SARS-CoV. Therefore, herein, we analysed the 3CLpro sequence, constructed its 3D homology model, and screened it against a medicinal plant library containing 32,297 potential anti-viral phytochemicals/traditional Chinese medicinal compounds. Our analyses revealed that the top nine hits might serve as potential anti- SARS-CoV-2 lead molecules for further optimisation and drug development process to combat COVID-19.

Gene isolation and prediction of the corresponding three-dimensional structure of subtilisin from the psychrophilic yeast, Glaciozyma antarctica PI12

Aims@#Subtilisin, a serine protease, is a key player in many industrial applications especially in the detergent industry. Most reported subtilisins originate from mesophilic and thermophilic microorganisms. Only scarce information about cold-active subtilisins from psychrophilic microbes is available. Here we describe the isolation, cloning and in silico characterisation of a gene encoding subtilisin in the obligate psychrophilic yeast, Glaciozyma antarctica PI12. @*Methodology and results@#A full-length cDNA from Glaciozyma antarctica encoding subtilisin (GaSUB) was isolated through Reverse-Transcription-Polymerase Chain Reaction (RT-PCR) techniques. The open reading frame of GaSUB comprised 1,125 nucleotides encoding 375 amino acids. The GaSUB amino acid sequence had 49% sequence identity with a subtilisin from the yeast, Puccinia striiformis. Bioinformatic analyses revealed that the GaSUB protein contains a domain that represents the S8 domain of the largest protease family. The predicted model of GaSUB protein using MODELLER and Pymol software revealed that this enzyme has longer loops and less intramolecular interactions between amino acid residues as compared to its mesophilic and thermophilic counterparts. These characteristics are known to help in protein flexibility and stability in cold-active enzymes. @*Conclusion, significance and impact of study@#Bioinformatics characterisations suggested that this enzyme is uniquely adapted to cold environments. Further work using amplified cDNA will be conducted to confirm the catalytic function of this enzyme.

Molecular Modeling, Structural Analysis and Evaluation of 1-Deoxy-D-Xylulose-5-Phosphate Reductoisomerase (DXR) as a Putative Drug Target For Theileria Parva

ABSTRACT The apicomplexan parasite Theileria parva, the causative agent of ECF, is an important pathogen affecting both domestic and wild animals, causing major economic losses in the world. Problems such as high cost of drugs, development of resistance, and absence of effective vaccines prevent effective combating of the pathogen. Thus, it is necessary to explore new targets for affordable and higher therapeutic value drugs. 1-Deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) in the non-mevalonate isoprene biosynthesis pathway is vital to the organism and therefore has been selected as a target for developing antitheilerial drugs. In this study, the 3D structure of TpDXR was identified by template-based in silico homology modelling method, the constructed model was validated and structurally analysed, and possible ligand binding pockets were identified for the first time in the literature. A reliable 3D model for TpLDH was modelled by using 3AU9 chain 'A' Plasmodium falciparum as a template. The obtained result showed that the model has a good resolution structure with 86.768 overall quality factor and a -9.15 z-score for TpDXR. The present study promises the possibility of exploiting new and safe inhibitors using the structure-based drug design that is effective against ECF through docking studies.

Homology Modeling and Docking Studies of Japanese Encephalitis Virus Proteins Like Envelope Protein and NS1 Protein.

Japanese Encephalitis (JE) is a vector- borne, viral zoonosis that may affect humans. The disease periodically becomes endemic in areas such as northern India, parts of central and southern India. Japanese Encephalitis virus belongs to the mostly vector-borne flaviviriade, which are single stranded RNA viruses. The envelope glycoprotein of JE Viruses contain specific as well as cross relative, neutralizing epitopes. The objective of this research to find out the best ligand molecule each for the two drug targeting protein present in the JEV. This will be done by studying the complete structure of JEV drug targeting proteins and their interaction with their respective ligand. The envelope protein and NS1 protein have been studied. The minimum energies were recorded after the docking studies for all the inhibitors docked with the protein. After comparison of the minimum energies recorded, the ligand with the least minimum docking energy has been considered as the best ligand. The entire study indicates that the inhibitor Mycophenolate with minimum energy -5.00605kj/mol is the most effective against Envelope protein. However in case of NS1 protein, the inhibitor Deoxynojirimycin with the minimum energy of - 6.75932kj/mol is found to be the most effective.

Structural and functional analysis of cathepsin S of Heterodera spp: A promising candidate for its control.

Cysteine proteinases are required for a wide range of physiological processes in all living organisms. In parasitic nematodes, they are particularly crucial for the digestion of host tissues and evasion of host immune responses. Therefore, in general, these are identified as primary targets for the control of parasitic nematodes. Herein, cathepsin S-like cysteine proteinase of Heterodera avenae (Hacp-s) has been cloned and analysed for the first time. The predicted protein is 298 amino acids long and showed significant similarity with cathepsin S of Heterodera glycines (Hgcp-s). The sequence of cathepsin S contains a signal peptide of 30 amino acids which suggests its role in extracellular functions. Multiple sequence alignment revealed the presence of ERFNIN motif and conserved catalytic residues. Three dimensional structure (3D) of Hgcp-s was modelled using homology modelling. In order to illustrate the plausible mode of interaction of cathepsin S (Hgcp-s), docking analysis was performed with E-64 cysteine proteinase inhibitor. Docking studies revealed the hydrogen bonding of E-64 with Gln153, His299 and Gly203 as well as close interaction with catalytic residues Cys159 and Asn320. Expression analysis of Hacp-s using qRT-PCR showed high expression of cathepsin S in pre parasitic J2s and female stages suggesting its significant role in both pre-parasitic and parasitic stages of the nematode life cycle.

Characterization of haemoglobin from Actinorhizal plants – An in silico approach.

Plant haemoglobins (Hbs), found in both symbiotic and non-symbiotic plants, are heme proteins and members of the globin superfamily. Hb genes of actinorhizal Fagales mostly belong to the non-symbiotic type of haemoglobin; however, along with the non-symbiotic Hb, Casuarina sp. posses a symbiotic one (symCgHb), which is expressed specifically in infected cells of nodules. A thorough sequence analysis of 26 plant Hb proteins, currently available in public domain, revealed a consensus motif of 29 amino acids. This motif is present in all the members of symbiotic class II Hbs including symCgHb and non-symbiotic Class II Hbs, but is totally absent in Class I symbiotic and non-symbiotic Hbs. Further, we constructed 3D structures of Hb proteins from Alnus and Casuarina through homology modelling and peeped into their structural properties. Structure-based studies revealed that the Casuarina symbiotic haemoglobin protein shows distinct stereochemical properties from that of the other Casuarina and Alnus Hb proteins. It also showed considerable structural similarities with leghemoglobin structure from yellow lupin (pdb id 1GDI). Therefore, sequence and structure analyses point to the fact that symCgHb protein shows significant resemblance to symbiotic haemoglobin found in legumes and may thus eventually play a similar role in shielding the nitrogenase from oxygen as seen in the case of leghemoglobin.

Modelling and drug designing of glutamate receptor involved in alzheimer’s disease.

Glutamate receptors dysfunction plays an important role in the pathogenesis and disturbance which is probably a secondary phenomenon to other neurochemical, genetic or metabolic changes, and essential to the development of Alzheimer Disease. Glutamate receptors are synaptic receptors, which are located on the membranes of neuronal cells. Glutamate is used to assemble proteins and also it is abundant in many areas of the body, but it also functions as a neurotransmitter and is particularly abundant in the nervous system. In this work we have modeled a three dimensional structure for Glutamate [NMDA] receptor subunit using MODELLER7V7 software with 2RC7 (Crystal Structure of the NR3A Ligand Binding Core Complex with Glycine) as template. With the aid of Molecular dynamics and Molecular simulations studies it was identified that the generated structure was reliable. This structure was used to identify better inhibitor using docking studies. The drug derivatives were docked to the Glutamate receptor structure into the active site containing residues such as ASP21, LEU30, TYR31, HIS59, and MET60. Among the 21 derivatives 14 were docked and 3rd drug derivative showed better docking energy than the others. Our experimental studies can be further used to develop a better drug for Alzheimer disease.

Homology modeling and drug designing of 18KDA antigen in mycobacterium leprae.

Most of the antigens of Mycobacterium leprae that have been identified are members of stress protein families. 18kDa antigen of M. leprae is an important antigen in the immune response to leprosy. This protein antigen of M. leprae is related to the family of small heat shock protein. To predict the structure of 18kDa antigen and to understand the mechanisms of inhibitors interaction, a threedimensional model was generated based on the Crystal Structure and assembly of eukaryotic small heat shock protein (PDB: 1GME) by using MODELLER7v7. The structure having a least modeller objective function was used as a starting point for picoseconds-duration molecular dynamics simulations. With the aid of the molecular dynamics and minimization methods, the final refined model was obtained and was further assessed by ERRAT, WHATCHECK and PROCHECK, which suggested that the refined model was reliable. Docking studies were performed by using the models with 2-mercaptoethanol and 3-amino- 5-methylhexanoic acid inhibitors. The results indicate that the 3-amino-5,5-diphenylpentanoic acid has more affinity than the other drug derivatives. The docking studies also suggest that MET-03, ARG-04, ASP-31, ALA-32, TRP-33, ARG-34, GLU-35 ARG-89, GLN-90 LEU-91 and VAL-92 are important determinant residues in binding with ligands. From the docking studies, we also suggest that GLU-35, in 18kDa protein domain is an important residue in binding.