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The anillin actin-binding protein (ANLN) is immensely overexpressed in cancers, including lung cancer (LC). Phytocompounds have gained interest due to their broader potential and reduced unwanted effects. Screening numerous compounds presents a challenge, but in silico molecular docking is pragmatic. The present study aims to identify the role of ANLN in lung adenocarcinoma (LUAD), along with identification and interaction analysis of anticancer and ANLN inhibitory phytocompounds followed by molecular dynamics (MD) simulation. Using a systematic approach, we found that ANLN is significantly overexpressed in LUAD and mutated with a frequency of 3.73%. It is linked with advanced stages, clinicopathological parameters, worsening of relapse-free survival (RFS), and overall survival (OS), pinpointing its oncogenic and prognostic potential. High-throughput screening and molecular docking of phytocompounds revealed that kaempferol (flavonoid aglycone) interacts strongly with the active site of ANLN protein via hydrogen bonds, Vander Waals interactions, and acts as a potent inhibitor. Furthermore, we discovered that ANLN expression was found to be significantly higher (p) in LC cells compared to normal cells. This is a propitious and first study to demonstrate ANLN and kaempferol interactions, which might eventually lead to removal of rout from cell cycle regulation posed by ANLN overexpression and allow it to resume normal processes of proliferation. Overall, this approach suggested a plausible biomarker role of ANLN and the combination of molecular docking subsequently led to the identification of contemporary phytocompounds, bearing symbolic anticancer effects. The findings would be advantageous for pharmaceutics but require validation using in vitro and in vivo methods. HIGHLIGHTS: ⢠ANLN is significantly overexpressed in LUAD. ⢠ANLN is implicated in the infiltration of TAMs and altering plasticity of TME. ⢠Kaempferol (potential ANLN inhibitor) shows important interactions with ANLN which could remove the alterations in cell cycle regulation, imposed by ANLN overexpression eventually leading to normal process of cell proliferation.
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Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Humanos , Proteínas dos Microfilamentos/metabolismo , Quempferóis , Prognóstico , Simulação de Acoplamento Molecular , Multiômica , Adenocarcinoma de Pulmão/tratamento farmacológico , Adenocarcinoma de Pulmão/genética , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismoRESUMO
The emergence of multidrug-resistant strains of Candida albicans has become a global threat mostly due to co-infection with immune-compromised patients leading to invasive candidiasis. The life-threatening form of the disease can be managed quickly and effectively by drug repurposing. Thus, the study used in silico approaches to evaluate Food and Drug Administration (FDA) approved drugs against three drug targets-TRR1, TOM40, and YHB1. The tertiary structures of three drug targets were modeled, refined, and evaluated for their structural integrity based on PROCHECK, ERRAT, and PROSA. High-throughput virtual screening of FDA-approved drugs (8815), interaction analysis, and energy profiles had revealed that DB01102 (Arbutamine), DB01611 (Hydroxychloroquine), and DB09319 (Carindacillin) exhibited better binding affinity with TRR1, TOM40, and YHB1, respectively. Notably, the molecular dynamic simulation explored that Gln45, Thr119, and Asp288 of TRR1; Thr107 and Ser121 of TOM40; Arg193, Glu213, and Ser228 of YHB1 are crucial residues for stable drug-target interaction. Additionally, it also prioritized Arbutamine-TRR1 as the best drug-target complex based on MM-PBSA (-52.72 kcal/mol), RMSD (2.43 Å), and radius of gyration (-21.49 Å) analysis. In-depth, PCA results supported the findings of molecular dynamic simulations. Interestingly, the conserved region (>70%) among the TRR1 sequences from pathogenic Candida species indicated the effectiveness of Arbutamine against multiple species of Candida as well. Thus, the study dispenses new insight and enriches the understanding of developing an advanced technique to consider potential antifungals against C. albicans. Nonetheless, a detailed experimental validation is needed to investigate the efficacy of Arbutamin against life-threatening candidiasis.
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Antifúngicos , Candida albicans/crescimento & desenvolvimento , Reposicionamento de Medicamentos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Antifúngicos/química , Antifúngicos/farmacologia , HumanosRESUMO
COVID-19 is a sneaking deadly disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The rapid increase in the number of infected patients worldwide enhances the exigency for medicines. However, precise therapeutic drugs are not available for COVID-19; thus, exhaustive research is critically required to unscramble the pathogenic tools and probable therapeutic targets for the development of effective therapy. This study utilizes a chemogenomics strategy, including computational tools for the identification of viral-associated differentially expressed genes (DEGs), and molecular docking of potential chemical compounds available in antiviral, anticancer, and natural product-based libraries against these DEGs. We scrutinized the messenger RNA expression profile of SARS-CoV-2 patients, publicly available on the National Center for Biotechnology Information-Gene Expression Omnibus database, stratified them into different groups based on the severity of infection, superseded by identification of overlapping mild and severe infectious (MSI)-DEGs. The profoundly expressed MSI-DEGs were then subjected to trait-linked weighted co-expression network construction and hub module detection. The hub module MSI-DEGs were then exposed to enrichment (gene ontology + pathway) and protein-protein interaction network analyses where Rho guanine nucleotide exchange factor 1 (ARHGEF1) gene conjectured in all groups and could be a probable target of therapy. Finally, we used the molecular docking and molecular dynamics method to identify inherent hits against the ARHGEF1 gene from antiviral, anticancer, and natural product-based libraries. Although the study has an identified significant association of the ARHGEF1 gene in COVID19; and probable compounds targeting it, using in silico methods, these targets need to be validated by both in vitro and in vivo methods to effectively determine their therapeutic efficacy against the devastating virus.
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Tratamento Farmacológico da COVID-19 , COVID-19 , COVID-19/genética , Ontologia Genética , Humanos , Simulação de Acoplamento Molecular , Fatores de Troca de Nucleotídeo Guanina Rho , SARS-CoV-2/genéticaRESUMO
Nature and nurture have always been a prerogative of evolutionary biologists. The environment's role in shaping an organism's phenotype has always intrigued us. Since the inception of humankind, twinning has existed with an unsettled parley on the contribution of nature (i.e. genetics) versus nurture (i.e. environment), which can influence the phenotypes. The study of twins measures the genetic contribution and that of the environmental influence for a particular trait, acting as a catalyst, fine-tuning the phenotypic trajectories. This is further evident because a number of human diseases show a spectrum of clinical manifestations with the same underlying molecular aberration. As of now, there is no definite way to conclude just from the genomic data the severity of a disease or even to predict who will get affected. This greatly justifies initiating a twin registry for a country as diverse and populated as India. There is an unmet need to set up a nationwide database to carefully curate the information on twins, serving as a valuable biorepository to study their overall susceptibility to disease. Establishing a twin registry is of paramount importance to harness the wealth of human information related to the biomedical, anthropological, cultural, social and economic significance.
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Doenças em Gêmeos , Gêmeos , Doenças em Gêmeos/epidemiologia , Doenças em Gêmeos/genética , Humanos , Índia/epidemiologia , Sistema de Registros , Gêmeos/genética , Recursos HumanosRESUMO
Wealth of structural data on theurapeutic targets in complex with monoclonal antibodies (mAbs) and advances in molecular modeling algorithms present exciting opportunities in the field of novel biologic design. Interleukin 23 (IL23), a well-known drug target for autoimmune diseases, in complex with mAb 7G10 offers prospect to design potent lead antibodies by traversing the complete epitope-paratope interface. Herein, key interactions aiding antibody-based neutralization in IL23-7G10 complex are resolute through PyMOL, LigPlot+, Antibody i-Patch, DiscoTope and FoldX. Six amino acids Ser31, Val33, Asn55, Lys59 in heavy chain and His34, Ser93 in light chain are subjected to in silico mutagenesis with residues Met, Trp, Ile, Leu and Arg. A set of 431 mutant macromolecules are outlined. Binding affinities of these molecules with IL23 are estimated through protein-protein docking by employing ZDOCK, ClusPro and RosettaDock. Subsequently, the macromolecules revealed comparable result with 7G10 are cross validated through binding free-energy calculations by applying Molecular Mechanics/Poisson Boltzman Surface Area method in CHARMM. Thirty nine designed theoretical antibodies showed improved outcome in all evaluations; from these, top 10 molecules showed at least nine unit better binding affinity compared to the known mAb. These molecules have the potential to act as lead antibodies. Subsequent molecular dynamics simulations too favored prospective of best ranked molecule to have therapeutic implications in autoimmune and inflammatory diseases. Abbreviations: IL23: interleukin 23; IL17: interleukin17; Ab: antibody; Ag: antigen; mAbs: monoclonal antibodies; STAT3: signal transducer and activator of transcription 3; STAT4: signal transducer and activator of transcription 4; PDB: protein databank; MM/PBSA: molecular mechanics Poisson-Boltzmann surface area; Ag-Ab: antigen- antibody complex; SPC/E: extended simple point charge; SD: steepest descents; PME: particle mesh ewald; dG: binding free energies; Fv: variable fragment.
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Anticorpos Monoclonais/imunologia , Doenças Autoimunes/imunologia , Inflamação/imunologia , Interleucina-23/química , Anticorpos Monoclonais/química , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/genética , Sítios de Ligação de Anticorpos , Biologia Computacional , Epitopos/química , Epitopos/imunologia , Humanos , Ligação de Hidrogênio , Inflamação/tratamento farmacológico , Inflamação/genética , Interleucina-23/imunologia , Simulação de Dinâmica Molecular , Fator de Transcrição STAT3/química , Fator de Transcrição STAT3/imunologia , Fator de Transcrição STAT4/química , Fator de Transcrição STAT4/imunologiaRESUMO
Psoriasis is a systemic hyperproliferative inflammatory skin disorder, although rarely fatal but significantly reduces quality of life. Understanding the full genetic component of the disease association may provide insight into biological pathways as well as targets and biomarkers for diagnosis, prognosis and therapy. Studies related to psoriasis associated genes and genetic markers are scattered and not easily amendable to data-mining. To alleviate difficulties, we have developed dbGAPs an integrated knowledgebase representing a gateway to psoriasis associated genomic data. The database contains annotation for 202 manually curated genes associated with psoriasis and its subtypes with cross-references. Functional enrichment of these genes, in context of Gene Ontology and pathways, provide insight into their important role in psoriasis etiology and pathogenesis. The dbGAPs interface is enriched with an interactive search engine for data retrieval along with unique customized tools for Single Nucleotide Polymorphism (SNP)/indel detection and SNP/indel annotations. dbGAPs is accessible at http://www.bmicnip.in/dbgaps/.
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Computer-aided antibody engineering has been successful in the design of new biologics for disease diagnosis and therapeutic interventions. Interleukin-6 (IL-6), a well-recognized drug target for various autoimmune and inflammatory diseases such as rheumatoid arthritis, multiple sclerosis, and psoriasis, was investigated in silico to design potential lead antibodies. Here, crystal structure of IL-6 along with monoclonal antibody olokizumab was explored to predict antigen-antibody (Ag - Ab)-interacting residues using DiscoTope, Paratome, and PyMOL. Tyr56, Tyr103 in heavy chain and Gly30, Ile31 in light chain of olokizumab were mutated with residues Ser, Thr, Tyr, Trp, and Phe. A set of 899 mutant macromolecules were designed, and binding affinity of these macromolecules to IL-6 was evaluated through Ag - Ab docking (ZDOCK, ClusPro, and Rosetta server), binding free-energy calculations using Molecular Mechanics/Poisson Boltzman Surface Area (MM/PBSA) method, and interaction energy estimation. In comparison to olokizumab, eight newly designed theoretical antibodies demonstrated better result in all assessments. Therefore, these newly designed macromolecules were proposed as potential lead antibodies to serve as a therapeutics option for IL-6-mediated diseases.
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Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais/química , Doenças Autoimunes/tratamento farmacológico , Inflamação/tratamento farmacológico , Interleucina-6/química , Anticorpos Monoclonais/metabolismo , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados/metabolismo , Anticorpos Monoclonais Humanizados/uso terapêutico , Doenças Autoimunes/metabolismo , Simulação por Computador , Cristalografia por Raios X , Humanos , Inflamação/metabolismo , Interleucina-6/antagonistas & inibidores , Interleucina-6/metabolismo , Chumbo/química , Conformação Proteica/efeitos dos fármacosRESUMO
BACKGROUND: Thrombotic disease is still a major killer. Aspirin, Ticagrelor, Clopidogrel, etc. are the most widely used conventional antiplatelet drugs. The significant number of patients who are resistant to this drug shows a poor outcome. OBJECTIVE: Developing a new antiplatelet agent with a stable antiplatelet effect and minimal bleeding risk is required for a patient who is resistant to antiplatelet drugs. METHOD: Protein-ligand docking was performed using Autodock Vina 1.1.2 to study the interaction of 67LR with different Polyphenols. RESULT: Among the 18 polyphenols, thearubigin has the highest binding affinity towards 67LR and gallic acid shows the lowest binding affinity. Among the 18 molecules, the top 10 molecules from the highest to lowest binding affinity range from-10.6 (thearubigin) to -6.5 (Epigallocatechin). CONCLUSION: Polyphenols may inhibit platelet aggregation through 67 LR and can be an alternative treatment for Thrombotic Disease. Moreover, it will be interesting to know whether polyphenols interfere with the same pathways as aspirin and clopidogrel. Effective polyphenols could help prototype the compound development of novel antiplatelet agents.
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We present N-imidazopyridine-noscapinoids, a new class of noscapine derivatives that bind to tubulin and exhibit antiproliferative activity against triple positive (MCF-7) and triple negative (MDA-MB-231) breast cancer cells. The N-atom of the isoquinoline ring of noscapine scaffold was altered in silico by coupling the imidazo [(Ye et al., 1998; Ke et al., 2000) 1,21,2-a] pyridine pharmacophore to rationally develop a series of N-imidazopyridine-noscapinoids (7-11) with high tubulin binding affinity. The predicted ΔGbinding of the N-imidazopyridine-noscapinoids 7-11 varied from -27.45 to -36.15 kcal/mol, a much lower value than noscapine with ΔGbinding -22.49 kcal/mol. The cytotoxicity of N-imidazopyridine-noscapinoids was evaluated using hormone dependent MCF-7, triple negative MDA-MB-231 breast cancer cell lines and primary breast cancer cells. The cytotoxicity of these compounds (represented as IC50 concentration) ranges between 4.04 and 33.93 µM against breast cancer cells without affecting normal cells (IC50 value > 952 µM). All the compounds (7-11) perturbed the cell cycle progression at G2/M phase and triggered apoptosis. Among all the N-imidazopyridine-noscapinoids, N-5-Bromoimidazopyridine-noscapine (9) showed promising antiproliferative activity and was selected for detailed investigation. The onset of apoptosis treated with 9 using MDA-MB-231 revealed morphological changes like cellular shrinkage, chromatin condensation, membrane blebbing, and apoptotic bodies formation. Along with elevated reactive oxygen species (ROS), there was a loss of mitochondrial membrane potential, suggesting induction of apoptosis to cancer cells. Compound 9 was also found to significantly regress the implanted tumour in nude mice as xenografts of MCF-7 cells without any apparent side effects after drug administration. We conclude that N-imidazopyridine-noscapinoids possess excellent potential as a promising drug for treating breast cancers.
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Antineoplásicos , Neoplasias da Mama , Noscapina , Humanos , Animais , Camundongos , Feminino , Tubulina (Proteína)/metabolismo , Noscapina/farmacologia , Noscapina/uso terapêutico , Xenoenxertos , Camundongos Nus , Microtúbulos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antineoplásicos/química , Piridinas/farmacologia , Piridinas/uso terapêutico , Neoplasias da Mama/patologia , Proliferação de Células , Linhagem Celular Tumoral , ApoptoseRESUMO
Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are lung complications diagnosed by impaired gaseous exchanges leading to mortality. From the diverse etiologies, sepsis is a prominent contributor to ALI/ARDS. In the present study, we retrieved sepsis-induced ARDS mRNA expression profile and identified 883 differentially expressed genes (DEGs). Next, we established an ARDS-specific weighted gene co-expression network (WGCN) and picked the blue module as our hub module based on highly correlated network properties. Later we subjected all hub module DEGs to form an ARDS-specific 3-node feed-forward loop (FFL) whose highest-order subnetwork motif revealed one TF (STAT6), one miRNA (miR-34a-5p), and one mRNA (TLR6). Thereafter, we screened a natural product library and identified three lead molecules that showed promising binding affinity against TLR6. We then performed molecular dynamics simulations to evaluate the stability and binding free energy of the TLR6-lead molecule complexes. Our results suggest these lead molecules may be potential therapeutic candidates for treating sepsis-induced ALI/ARDS. In-silico studies on clinical datasets for sepsis-induced ARDS indicate a possible positive interaction between miR-34a and TLR6 and an antagonizing effect on STAT6 to promote inflammation. Also, the translational study on septic mice lungs by IHC staining reveals a hike in the expression of TLR6. We report here that miR-34a actively augments the effect of sepsis on lung epithelial cell apoptosis. This study suggests that miR-34a promotes TLR6 to heighten inflammation in sepsis-induced ALI/ARDS. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03700-1.
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The scaffold structure of noscapine (an antitussive plant alkaloid) was modified by inducting N-aryl methyl pharmacophore at C-9 position of the isoquinoline ring to rationally design and screened three novel 9-(N-arylmethylamino) noscapinoids, 15-17 with robust binding affinity with tubulin. The selected 9-(N-arylmethylamino) noscapinoids revealed improved predicted binding energy of -6.694 kcal/mol for 15, -7.118 kcal/mol for 16 and -7.732 kcal/mol for 17, respectively in comparison to the lead molecule (-5.135 kcal/mol). These novel derivatives were chemically synthesized and validated their anticancer activity based on cellular studies using two human breast adenocarcinoma, MCF-7 and MDA-MB-231, as well as with a panel of primary breast tumor cells. These derivatives inhibited cellular proliferation in all the cancer cells that ranged between 3.2 and 32.2 µM, which is 11.9 to 1.8 fold lower than that of noscapine. These novel derivatives effectively arrest the cell cycle in the G2/M phase followed by apoptosis and appearance of apoptotic cells. Thus, we conclude that 9-(N-arylmethyl amino) noscapinoids, 15-17 have a high probability to be a novel therapeutic agent for breast cancers.
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Aminas/química , Antineoplásicos/síntese química , Desenho de Fármacos , Noscapina/análogos & derivados , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Humanos , Simulação de Acoplamento Molecular , Noscapina/metabolismo , Noscapina/farmacologia , Ligação Proteica , Relação Estrutura-Atividade , Termodinâmica , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismoRESUMO
Alkaptonuria (AKU) is an autosomal recessive disorder, which is caused by a site-specific mutation(s) and thus, impaired the function of Homogentisate-1, 2-dioxygenase (HGD), an essential enzyme for the catabolism of phenylalanine and tyrosine. Among frameshift, intronic, splice-site and missense mutations, the latter has been the most common form of genetic variations for the disease. How do the acquired mutations in HGD correlate with the disease? Systematic staged-screening of some sixty-five mutations, which are known to have a relation with the disease, by GVGD, SIFT, SNAP, PANTHER, SDM, PHD-SNP, Meta-SNP, Pmut and Mutpred methods, showed that mutations, W60G, A122D and V300G are potentially related with the severity of AKU. Detailed analyses on molecular docking and molecular dynamics simulation (MDS) of these mutants against the wild-type HGD reveal the loss of structural and molecular dynamic properties of the enzyme. Further, the observed conformational flexibility in mutants at targeted peptide segments seems to have a relation with the impairment of the function of HGD. Taken together, the study involves a designed computational methodology to analyse the disease-associated nsSNPs for AKU, the knowledge of which seems to have potential applications in drug therapies for the disease in particular and other similar systems in general.Communicated by Ramaswamy H. Sarma.
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Alcaptonúria , Homogentisato 1,2-Dioxigenase/genética , Genes Letais , Humanos , Simulação de Acoplamento Molecular , MutaçãoRESUMO
Paromomycin, an aminoglycoside antibiotic, is an effective treatment for VL (visceral leishmaniasis) in India. The modification of aminoglycoside antibiotics by enzymes such as aminoglycoside acetyltransferases is the predominant mechanism of resistance to antibiotics in bacterial system. In the present study, we identified and characterized LdATLP (an acetyltransferase-like protein) and elucidated its role in paromomycin resistance in Leishmania donovani. Gene encoding LdATLP was consistently up-regulated (>2fold) in three distinct paromomycin resistant in comparison with sensitive parasites, although the gene sequence was identical in the two. In silico analysis revealed that LdATLP consisted of conserved GNAT (GCN5-related N-Acetyltransferase) domain which is characteristic of aminoglycoside N-acetyltransferases. Evolutionary relationship among LdATLP of Leishmania and aminoglycoside acetyltransferases of bacteria was established by phylogenetic analysis. The 3D structure of LdATLP, predicted by ab-initio modeling, constituted 6 α-helices and 6 ß-sheets. A few residues, such as R175, R177, E196, R197, V198, V200, K202, R205, C206, D208, G210, R211, R215, A234, S237, S238, K239, D240, F241 and Y242 of GNAT domain were predicted to be present at active site. Molecular docking of LdATLP with paromomycin or indolicidin (broad spectrum inhibitor of aminoglycoside modifying enzymes), followed by molecular dynamics simulation of docked complex suggested that both paromomycin and indolicidin bind to LdATLP with comparable free energy of binding. In vitro studies revealed that in the presence of indolicidin, paromomycin resistant parasites exhibited reversion of phenotype into sensitive parasites with marked increase in paromomycin susceptibility, suggesting the role of LdATLP in paromomycin resistance.Communicated by Ramaswamy H. Sarma.
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Antiprotozoários , Leishmania donovani , Acetiltransferases/genética , Antiprotozoários/farmacologia , Resistência a Medicamentos/genética , Índia , Simulação de Acoplamento Molecular , Paromomicina/farmacologia , FilogeniaRESUMO
UNLABELLED: Component (bridge: ΔΔGbrd , background: ΔΔGprot , desolvation: ΔΔGdsolv ) and net (ΔΔGnet ) energy-terms of salt-bridge-structure (SBS) are auto-generated by the program ADSBET that makes use of general purpose Adaptive Poison Boltzmann Solver (APBS) method. While the procedure reports gross energy terms (Kcal Mol(-1) ), report on bond-multiplicity corrected normalized energyterms (Kcal Mol(-1) Bond(-1) ) along with their accessibility (ASA) in monomer, isolated-SBS (ISBS) and networked-SBS (NSBS) format would be very useful for statistical comparison among SBSs and understanding their location in protein structure. In this end, ADSBET2 potentially incorporates these features along with additional model for side-chain. Gross and normalized energy-terms are redirected in monomer, ISBS and NSBS format along with their ASA informations. It works on any number of SBSs for any number of structure files present in a database. Taken together, ADSBET2 has been suitable for statistical analyses of SBSs energetics and finds applications in protein engineering and structural bioinformatics. AVAILABILITY: ADSBET2 is freely available at http://sourceforge.net/projects/ADSBET2/ for all users.
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UNLABELLED: Specific electrostatics (i.e. salt-bridge) includes both local and non-local interactions that contribute to the overall stability of proteins. It has been shown that a salt-bridge could either be buried or exposed, networked or isolated, hydrogen-bonded or nonhydrogen bonded, in secondary-structure or in coil, formed by single or multiple bonds. Further it could also participates either in intra- or inter-dipole interactions with preference in orientation either for basic residue at N-terminal (orientation-I) or acidic residue at N-terminal (orientation-II). In this context SBION2 is unique in that it reports above mentioned binary items in excel format along with details on intra and inter-dipole interactions and orientations. These results are suitable for post run statistical analyses involving large datasets. Reports are also made on protein-protein interactions, intervening residue distances and general residue specific salt-bridge details. A ready to use compact supplementary table is also produced. The program runs in three alternative modes. Each mode works on any number of structure files with any number of chains at any given atomic distance of ion-pair. Thus SBION2 provides intricate details on salt-bridges and finds application in structural bioinformatics. AVAILABILITY: SBION2 is freely available at http://sourceforge.net/projects/sbion2/ for academic users.
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UNLABELLED: Automated genome sequencing procedure is enriching the sequence database very fast. To achieve a balance between the entry of sequences in the database and their analyses, efficient software is required. In this end PHYSICO2, compare to earlier PHYSICO and other public domain tools, is most efficient in that it i] extracts physicochemical, window-dependent and homologousposition-based-substitution (PWS) properties including positional and BLOCK-specific diversity and conservation, ii] provides users with optional-flexibility in setting relevant input-parameters, iii] helps users to prepare BLOCK-FASTA-file by the use of Automated Block Preparation Tool of the program, iv] performs fast, accurate and user-friendly analyses and v] redirects itemized outputs in excel format along with detailed methodology. The program package contains documentation describing application of methods. Overall the program acts as efficient PWS-analyzer and finds application in sequence-bioinformatics. AVAILABILITY: PHYSICO2: is freely available at http://sourceforge.net/projects/physico2/ along with its documentation at https://sourceforge.net/projects/physico2/files/Documentation.pdf/download for all users.
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Halophilic proteins have greater abundance of acidic over basic and very low bulky hydrophobic residues. Classical electrostatic stabilization was suggested as the key determinant for halophilic adaptation of protein. However, contribution of specific electrostatic interactions (i.e. salt-bridges) to overall stability of halophilic proteins is yet to be understood. To understand this, we use Adaptive-Poison-Boltzmann-Solver Methods along with our home-built automation to workout net as well as associated component energy terms such as desolvation energy, bridge energy and background energy for 275 salt-bridges from 20 extremely halophilic proteins. We then perform extensive statistical analysis on general and energetic attributes on these salt-bridges. On average, 8 salt-bridges per 150 residues protein were observed which is almost twice than earlier report. Overall contributions of salt-bridges are -3.0 kcal mol-1. Majority (78%) of salt-bridges in our dataset are stable and conserved in nature. Although, average contributions of component energy terms are equal, their individual details vary greatly from one another indicating their sensitivity to local micro-environment. Notably, 35% of salt-bridges in our database are buried and stable. Greater desolvation penalty of these buried salt-bridges are counteracted by stable network salt-bridges apart from favorable equal contributions of bridge and background terms. Recruitment of extensive network salt-bridges (46%) with a net contribution of -5.0 kcal mol-1 per salt-bridge, seems to be a halophilic design wherein favorable average contribution of background term (-10 kcal mol-1) exceeds than that of bridge term (-7 kcal mol-1). Interiors of proteins from halophiles are seen to possess relatively higher abundance of charge and polar side chains than that of mesophiles which seems to be satisfied by cooperative network salt-bridges. Overall, our theoretical analyses provide insight into halophilic signature in its specific electrostatic interactions which we hope would help in protein engineering and bioinformatics studies.