MANISH DWIVEDI | University of Allahabad (original) (raw)
Papers by MANISH DWIVEDI
Infection and Drug Resistance
Bacteria survive on any surface through the generation of biofilms that provide a protective envi... more Bacteria survive on any surface through the generation of biofilms that provide a protective environment to grow as well as making them drug resistant. Extracellular polymeric matrix is a crucial component in biofilm formation. The presence of biofilms consisting of common opportunistic and nosocomial, drug-resistant pathogens has been reported on medical devices like catheters and prosthetics, leading to many complications. Several approaches are under investigation to combat drug-resistant bacteria. Deployment of bacteriophages is one of the promising approaches to invade biofilm that may expose bacteria to the conditions adverse for their growth. Penetration into these biofilms and their destruction by bacteriophages is brought about due to their small size and ability of their progeny to diffuse through the bacterial cell wall. The other mechanisms employed by phages to infect biofilms may include their relocation through water channels to embedded host cells, replication at local sites followed by infection to the neighboring cells and production of depolymerizing enzymes to decompose viscous biofilm matrix, etc. Various research groups are investigating intricacies involved in phage therapy to mitigate the bacterial infection and biofilm formation. Thus, bacteriophages represent a good control over different biofilms and further understanding of phage-biofilm interaction at molecular level may overcome the clinical challenges in phage therapy. The present review summarizes the comprehensive details on dynamic interaction of phages with bacterial biofilms and the role of phage-derived enzymes-endolysin and depolymerases in extenuating biofilms of clinical and medical concern. The methodology employed was an extensive literature search, using several keywords in important scientific databases, such as Scopus, Web of Science, PubMed, ScienceDirect, etc. The keywords were also used with Boolean operator "And". More than 250 relevant and recent articles were selected and reviewed to discuss the evidence-based data on the application of phage therapy with recent updates, and related potential challenges.
Micromachines
DNA-mediated self-assembly of colloids has emerged as a powerful tool to assemble the materials o... more DNA-mediated self-assembly of colloids has emerged as a powerful tool to assemble the materials of prescribed structure and properties. The uniqueness of the approach lies in the sequence-specific, thermo-reversible hybridization of the DNA-strands based on Watson–Crick base pairing. Grafting particles with DNA strands, thus, results into building blocks that are fully programmable, and can, in principle, be assembled into any desired structure. There are, however, impediments that hinder the DNA-grafted particles from realizing their full potential, as building blocks, for programmable self-assembly. In this short review, we focus on these challenges and highlight the research around tackling these challenges.
Scientific Reports, 2021
Na+/H+ antiporters comprise a family of membrane proteins evolutionarily conserved in all kingdom... more Na+/H+ antiporters comprise a family of membrane proteins evolutionarily conserved in all kingdoms of life that are essential in cellular ion homeostasis. While several human homologues have long been drug targets, NhaA of Escherichia coli has become the paradigm for this class of secondary active transporters as NhaA crystals provided insight in the structure of this molecular machine. However, structural data revealing the composition of the binding site for Na+ (or its surrogate Li+) is missing, representing a bottleneck in our understanding of the correlation between the structure and function of NhaA. Here, by adapting the scintillation proximity assay (SPA) for direct determination of Na+ binding to NhaA, we revealed that (i) NhaA is well adapted as the main antiporter for Na+ homeostasis in Escherichia coli and possibly in other bacteria as the cytoplasmic Na+ concentration is similar to the Na+ binding affinity of NhaA, (ii) experimental conditions affect NhaA-mediated catio...
Journal of Neonatology, 2020
Coronavirus disease 19 (COVID-19) infection pandemic has affected remarkable morbidity and mortal... more Coronavirus disease 19 (COVID-19) infection pandemic has affected remarkable morbidity and mortality in a very short span of time. The overall disease profile and epidemiology is yet evolving but it seems to be highly infectious. Perinatal coronavirus infection is altogether a different perspective which has to be taken care of in a different way.
Nature Communications, 2018
Cation/proton antiporters (CPAs) play a major role in maintaining living cells' homeostasis. CPAs... more Cation/proton antiporters (CPAs) play a major role in maintaining living cells' homeostasis. CPAs are commonly divided into two main groups, CPA1 and CPA2, and are further characterized by two main phenotypes: ion selectivity and electrogenicity. However, tracing the evolutionary relationships of these transporters is challenging because of the high diversity within CPAs. Here, we conduct comprehensive evolutionary analysis of 6537 representative CPAs, describing the full complexity of their phylogeny, and revealing a sequence motif that appears to determine central phenotypic characteristics. In contrast to previous suggestions, we show that the CPA1/CPA2 division only partially correlates with electrogenicity. Our analysis further indicates two acidic residues in the binding site that carry the protons in electrogenic CPAs, and a polar residue in the unwound transmembrane helix 4 that determines ion selectivity. A rationally designed triple mutant successfully converted the electrogenic CPA, EcNhaA, to be electroneutral.
Biophysical Journal, 2019
Sodium-solute symporters (SSS) exploit the sodium ion concentration gradients to transports solut... more Sodium-solute symporters (SSS) exploit the sodium ion concentration gradients to transports solute across the plasma membrane. Through a series of conformational changes, collectively described as alternating access, transporters expose their substrate cavity from one side to the other of the membrane, and eventually release their cargo. How substrates and energizing ions coordinate to drive this processes remains elusive and is likely very different from one structural family to the next. I will use the Weighted Ensemble enhanced sampling technique together with a novel progress coordinate based on structural similarity to simulate alternating access of the bacterial sodium galactose transporter (vSGLT) starting from the apo and sugar bound inward-facing states using the outward-facing structure of the closely related sialic acid transporter (SiaT) as a target. Thanks to these two structures we can explore the biophysics of the transport cycle at the atomic level to answer to the following questions: 1) what is the order of binding?, and 2) how does sodium and substrate coupling drive conformational change? It is very likely that information gained through these studies will shed light on the transport cycle of mammalian homologues (hSGLT1/2) and other members in the Leucine Transporter superfamily.
Journal of Biological Chemistry, 2018
Journal of molecular biology, Jan 16, 2018
Na/H antiporters have a crucial role in pH and Na homeostasis in cells. The crystal structure of ... more Na/H antiporters have a crucial role in pH and Na homeostasis in cells. The crystal structure of NhaA, the main antiporter of Escherichia coli, has provided general insights into antiporter mechanisms and revealed a previously unknown structural fold, which has since been identified in several secondary active transporters. This unique structural fold is very delicately electrostatically balanced. Asp133 and Lys 300 have been ascribed essential roles in this balance and, more generally, in the structure and function of the antiporter. In this work, we show the multiple roles of Asp133 in NhaA: (i) The residue's negative charge is critical for the stability of the NhaA structure. (ii) Its main chain is part of the active site. (iii) Its side chain functions as an alkaline-pH-dependent gate, changing the protein's conformation from an inward-facing conformation at acidic pH to an outward-open conformation at alkaline pH, opening the periplasm funnel. On the basis of the experi...
Journal of Biological Chemistry, 2017
Edited by Thomas Söllner Na ؉ /H ؉ antiporters are located in the cytoplasmic and intracellular m... more Edited by Thomas Söllner Na ؉ /H ؉ antiporters are located in the cytoplasmic and intracellular membranes and play crucial roles in regulating intracellular pH, Na ؉ , and volume. The NhaA antiporter of Escherichia coli is the best studied member of the Na ؉ /H ؉ exchanger family and a model system for all related Na ؉ /H ؉ exchangers, including eukaryotic representatives. Several amino acid residues are important for the transport activity of NhaA, including Lys-300, a residue that has recently been proposed to carry one of the two H ؉ ions that NhaA exchanges for one Na ؉ ion during one transport cycle. Here, we sought to characterize the effects of mutating Lys-300 of NhaA to amino acid residues containing side chains of different polarity and length (i.e. Ala, Arg, Cys, His, Glu, and Leu) on transporter stability and function. Salt resistance assays, acridine-orange fluorescence dequenching, solid supported membrane-based electrophysiology, and differential scanning fluorometry were used to characterize Na ؉ and H ؉ transport, charge translocation, and thermal stability of the different variants. These studies revealed that NhaA could still perform electrogenic Na ؉ /H ؉ exchange even in the absence of a protonatable residue at the Lys-300 position. However, all mutants displayed lower thermal stability and reduced ion transport activity compared with the wild-type enzyme, indicating the critical importance of Lys-300 for optimal NhaA structural stability and function. On the basis of these experimental data, we propose a tentative mechanism integrating the functional and structural role of Lys-300.
Methods in Enzymology, 2015
Living cells are critically dependent on processes that regulate intracellular pH, Na(+) content,... more Living cells are critically dependent on processes that regulate intracellular pH, Na(+) content, and volume. Na(+)/H(+) antiporters play a primary role in these homeostatic mechanisms. They are found in the cytoplasmic and intracellular membranes of most organisms from bacteria to humans and have long been human drug targets. NhaA, the principal Na(+)/H(+) antiporter in Escherichia coli, plays an essential role in homeostasis of Na(+) and H(+). It constitutes a paradigm for the study of its numerous prokaryotic homologs and of several human Na(+)/H(+) antiporters. The crystal structure of NhaA, determined at pH4, has provided the first structural and functional insights into the antiport mechanism and pH regulation of an Na(+)/H(+) antiporter. Remarkably, the NhaA structure revealed a new and unique fold (the "NhaA fold") that has since been observed in four additional bacterial secondary transporters. The NhaA structure has facilitated the rational interpretation of mutational data obtained in NhaA, revealing the antiporter's functional organization. Nevertheless, the crystal structure is a single snapshot, determined at acidic pH, when NhaA is downregulated; NhaA is activated at pH6.5 and reaches maximal activity at pH8.5. Therefore, it is crucial to crystallize the active conformations of NhaA. Herein, we present a procedure for determining the structure of NhaA.
GPI anchors consist of three parts; protein, glycan and the phospholipids. The GPI anchored prote... more GPI anchors consist of three parts; protein, glycan and the phospholipids. The GPI anchored proteins work as cell surface hydrolases, protozoal antigens, adhesion molecules, mammalian antigens and involved in other significant cellular functions like dense packing of proteins on cell surface, increased protein mobility on cell surface , specific release from cell surface, control of exit from endoplasmic reticulum and toxin binding. Mutations in these proteins lead to Paroxysomal Nocturnal Haemogolbinuria and other disorders. This study was executed by combining comparative proteomics and phylogenetic approaches in order to address a cross family evolution of GPI anchor proteins from 23 different species. The results of revealed some unexplored specifics about the conserved domains GPI anchored proteins across different taxa of organisms. The results also demonstrated hierarchical assemblage based inconsistency in variation in the GPI anchored proteins
Advanced Science Letters, 2012
Scientific reports, Jan 29, 2016
The Na(+), Li(+)/H(+) antiporter of Escherichia coli (Ec-NhaA) maintains pH, Na(+) homeostasis in... more The Na(+), Li(+)/H(+) antiporter of Escherichia coli (Ec-NhaA) maintains pH, Na(+) homeostasis in enterobacteria. We used isothermal titration calorimetry to perform a detailed thermodynamic analysis of Li(+) binding to Ec-NhaA and several of its mutants. We found that, in line with the canonical alternative access mechanistic model of secondary transporters, Li(+)/H(+) binding to the antiporter is antagonistically coupled. Binding of Li(+) displaces 2 H(+) from the binding site. The process is enthalpically driven, the enthalpic gain just compensating for an entropic loss and the buffer-associated enthalpic changes dominate the overall free-energy change. Li(+) binding, H(+) release and antiporter activity were all affected to the same extent by mutations in the Li(+) binding site (D163E, D163N, D164N, D164E), while D133C changed the H(+)/Li(+) stoichiometry to 4. Most striking, however, was the mutation, A167P, which converted the Ec-NhaA antagonistic binding into synergistic bind...
Molecular Epidemiology Study of Mycobacterium Tuberculosis Complex, 2021
Tuberculosis (TB) is one of the deadly diseases in the present era caused by Mycobacterium tuberc... more Tuberculosis (TB) is one of the deadly diseases in the present era caused by Mycobacterium tuberculosis. Principally, this bacterium attacks the lungs, however, MTB Has been observed affecting any part of the human body including the kidney, spine, and brain. Drug-resistant progression and other associated properties of MTB become a major hurdle in drug discovery to fight against tuberculosis. Moreover, some of the challenging situations such as the low range of chemical agents, the time-consuming process of drug development, the shortage of predictive animal models, and inadequate information of the physicochemical evidence required for effective bacterial penetration, are additional hindrances for the pharmaceutical scientist. In the current chapter, we focus on challenges encountered during drug discovery and need to be overcome as M. tuberculosis has a substantial barrier in its lipid-containing cell wall to inhibit the influx of drugs which is the initial requirement of the dru...
Letters in Applied Microbiology, 2021
The interest in the working and functionality of the human gut microbiome has increased drastical... more The interest in the working and functionality of the human gut microbiome has increased drastically over the years. Though the existence of gut microbes has long been speculated for long over the last few decades, a lot of research has sprung up in studying and understanding the role of gut microbes in the human digestive tract. The microbes present in the gut are highly instrumental in maintaining the metabolism in the body. Further research is going on in this field to understand how gut microbes can be employed as potential sources of novel therapeutics, moreover, probiotics have also elucidated their significant place in this direction. As regards the clinical perspective, microbes can be engineered to afford defense mechanisms while interacting with foreign pathogenic bodies. More investigations in this field may assist us to evaluate and understand how these cells communicate with human cells and promote immune interactions. Here we elaborate on the possible implication of human gut microbiota into the immune system as well as explore the probiotics in the various human ailments. Comprehensive information on the human gut microbiome at the same platform may contribute affectively to our understanding of the human microbiome and possible mechanisms of associated human diseases.
Infection and Drug Resistance
Bacteria survive on any surface through the generation of biofilms that provide a protective envi... more Bacteria survive on any surface through the generation of biofilms that provide a protective environment to grow as well as making them drug resistant. Extracellular polymeric matrix is a crucial component in biofilm formation. The presence of biofilms consisting of common opportunistic and nosocomial, drug-resistant pathogens has been reported on medical devices like catheters and prosthetics, leading to many complications. Several approaches are under investigation to combat drug-resistant bacteria. Deployment of bacteriophages is one of the promising approaches to invade biofilm that may expose bacteria to the conditions adverse for their growth. Penetration into these biofilms and their destruction by bacteriophages is brought about due to their small size and ability of their progeny to diffuse through the bacterial cell wall. The other mechanisms employed by phages to infect biofilms may include their relocation through water channels to embedded host cells, replication at local sites followed by infection to the neighboring cells and production of depolymerizing enzymes to decompose viscous biofilm matrix, etc. Various research groups are investigating intricacies involved in phage therapy to mitigate the bacterial infection and biofilm formation. Thus, bacteriophages represent a good control over different biofilms and further understanding of phage-biofilm interaction at molecular level may overcome the clinical challenges in phage therapy. The present review summarizes the comprehensive details on dynamic interaction of phages with bacterial biofilms and the role of phage-derived enzymes-endolysin and depolymerases in extenuating biofilms of clinical and medical concern. The methodology employed was an extensive literature search, using several keywords in important scientific databases, such as Scopus, Web of Science, PubMed, ScienceDirect, etc. The keywords were also used with Boolean operator "And". More than 250 relevant and recent articles were selected and reviewed to discuss the evidence-based data on the application of phage therapy with recent updates, and related potential challenges.
Micromachines
DNA-mediated self-assembly of colloids has emerged as a powerful tool to assemble the materials o... more DNA-mediated self-assembly of colloids has emerged as a powerful tool to assemble the materials of prescribed structure and properties. The uniqueness of the approach lies in the sequence-specific, thermo-reversible hybridization of the DNA-strands based on Watson–Crick base pairing. Grafting particles with DNA strands, thus, results into building blocks that are fully programmable, and can, in principle, be assembled into any desired structure. There are, however, impediments that hinder the DNA-grafted particles from realizing their full potential, as building blocks, for programmable self-assembly. In this short review, we focus on these challenges and highlight the research around tackling these challenges.
Scientific Reports, 2021
Na+/H+ antiporters comprise a family of membrane proteins evolutionarily conserved in all kingdom... more Na+/H+ antiporters comprise a family of membrane proteins evolutionarily conserved in all kingdoms of life that are essential in cellular ion homeostasis. While several human homologues have long been drug targets, NhaA of Escherichia coli has become the paradigm for this class of secondary active transporters as NhaA crystals provided insight in the structure of this molecular machine. However, structural data revealing the composition of the binding site for Na+ (or its surrogate Li+) is missing, representing a bottleneck in our understanding of the correlation between the structure and function of NhaA. Here, by adapting the scintillation proximity assay (SPA) for direct determination of Na+ binding to NhaA, we revealed that (i) NhaA is well adapted as the main antiporter for Na+ homeostasis in Escherichia coli and possibly in other bacteria as the cytoplasmic Na+ concentration is similar to the Na+ binding affinity of NhaA, (ii) experimental conditions affect NhaA-mediated catio...
Journal of Neonatology, 2020
Coronavirus disease 19 (COVID-19) infection pandemic has affected remarkable morbidity and mortal... more Coronavirus disease 19 (COVID-19) infection pandemic has affected remarkable morbidity and mortality in a very short span of time. The overall disease profile and epidemiology is yet evolving but it seems to be highly infectious. Perinatal coronavirus infection is altogether a different perspective which has to be taken care of in a different way.
Nature Communications, 2018
Cation/proton antiporters (CPAs) play a major role in maintaining living cells' homeostasis. CPAs... more Cation/proton antiporters (CPAs) play a major role in maintaining living cells' homeostasis. CPAs are commonly divided into two main groups, CPA1 and CPA2, and are further characterized by two main phenotypes: ion selectivity and electrogenicity. However, tracing the evolutionary relationships of these transporters is challenging because of the high diversity within CPAs. Here, we conduct comprehensive evolutionary analysis of 6537 representative CPAs, describing the full complexity of their phylogeny, and revealing a sequence motif that appears to determine central phenotypic characteristics. In contrast to previous suggestions, we show that the CPA1/CPA2 division only partially correlates with electrogenicity. Our analysis further indicates two acidic residues in the binding site that carry the protons in electrogenic CPAs, and a polar residue in the unwound transmembrane helix 4 that determines ion selectivity. A rationally designed triple mutant successfully converted the electrogenic CPA, EcNhaA, to be electroneutral.
Biophysical Journal, 2019
Sodium-solute symporters (SSS) exploit the sodium ion concentration gradients to transports solut... more Sodium-solute symporters (SSS) exploit the sodium ion concentration gradients to transports solute across the plasma membrane. Through a series of conformational changes, collectively described as alternating access, transporters expose their substrate cavity from one side to the other of the membrane, and eventually release their cargo. How substrates and energizing ions coordinate to drive this processes remains elusive and is likely very different from one structural family to the next. I will use the Weighted Ensemble enhanced sampling technique together with a novel progress coordinate based on structural similarity to simulate alternating access of the bacterial sodium galactose transporter (vSGLT) starting from the apo and sugar bound inward-facing states using the outward-facing structure of the closely related sialic acid transporter (SiaT) as a target. Thanks to these two structures we can explore the biophysics of the transport cycle at the atomic level to answer to the following questions: 1) what is the order of binding?, and 2) how does sodium and substrate coupling drive conformational change? It is very likely that information gained through these studies will shed light on the transport cycle of mammalian homologues (hSGLT1/2) and other members in the Leucine Transporter superfamily.
Journal of Biological Chemistry, 2018
Journal of molecular biology, Jan 16, 2018
Na/H antiporters have a crucial role in pH and Na homeostasis in cells. The crystal structure of ... more Na/H antiporters have a crucial role in pH and Na homeostasis in cells. The crystal structure of NhaA, the main antiporter of Escherichia coli, has provided general insights into antiporter mechanisms and revealed a previously unknown structural fold, which has since been identified in several secondary active transporters. This unique structural fold is very delicately electrostatically balanced. Asp133 and Lys 300 have been ascribed essential roles in this balance and, more generally, in the structure and function of the antiporter. In this work, we show the multiple roles of Asp133 in NhaA: (i) The residue's negative charge is critical for the stability of the NhaA structure. (ii) Its main chain is part of the active site. (iii) Its side chain functions as an alkaline-pH-dependent gate, changing the protein's conformation from an inward-facing conformation at acidic pH to an outward-open conformation at alkaline pH, opening the periplasm funnel. On the basis of the experi...
Journal of Biological Chemistry, 2017
Edited by Thomas Söllner Na ؉ /H ؉ antiporters are located in the cytoplasmic and intracellular m... more Edited by Thomas Söllner Na ؉ /H ؉ antiporters are located in the cytoplasmic and intracellular membranes and play crucial roles in regulating intracellular pH, Na ؉ , and volume. The NhaA antiporter of Escherichia coli is the best studied member of the Na ؉ /H ؉ exchanger family and a model system for all related Na ؉ /H ؉ exchangers, including eukaryotic representatives. Several amino acid residues are important for the transport activity of NhaA, including Lys-300, a residue that has recently been proposed to carry one of the two H ؉ ions that NhaA exchanges for one Na ؉ ion during one transport cycle. Here, we sought to characterize the effects of mutating Lys-300 of NhaA to amino acid residues containing side chains of different polarity and length (i.e. Ala, Arg, Cys, His, Glu, and Leu) on transporter stability and function. Salt resistance assays, acridine-orange fluorescence dequenching, solid supported membrane-based electrophysiology, and differential scanning fluorometry were used to characterize Na ؉ and H ؉ transport, charge translocation, and thermal stability of the different variants. These studies revealed that NhaA could still perform electrogenic Na ؉ /H ؉ exchange even in the absence of a protonatable residue at the Lys-300 position. However, all mutants displayed lower thermal stability and reduced ion transport activity compared with the wild-type enzyme, indicating the critical importance of Lys-300 for optimal NhaA structural stability and function. On the basis of these experimental data, we propose a tentative mechanism integrating the functional and structural role of Lys-300.
Methods in Enzymology, 2015
Living cells are critically dependent on processes that regulate intracellular pH, Na(+) content,... more Living cells are critically dependent on processes that regulate intracellular pH, Na(+) content, and volume. Na(+)/H(+) antiporters play a primary role in these homeostatic mechanisms. They are found in the cytoplasmic and intracellular membranes of most organisms from bacteria to humans and have long been human drug targets. NhaA, the principal Na(+)/H(+) antiporter in Escherichia coli, plays an essential role in homeostasis of Na(+) and H(+). It constitutes a paradigm for the study of its numerous prokaryotic homologs and of several human Na(+)/H(+) antiporters. The crystal structure of NhaA, determined at pH4, has provided the first structural and functional insights into the antiport mechanism and pH regulation of an Na(+)/H(+) antiporter. Remarkably, the NhaA structure revealed a new and unique fold (the "NhaA fold") that has since been observed in four additional bacterial secondary transporters. The NhaA structure has facilitated the rational interpretation of mutational data obtained in NhaA, revealing the antiporter's functional organization. Nevertheless, the crystal structure is a single snapshot, determined at acidic pH, when NhaA is downregulated; NhaA is activated at pH6.5 and reaches maximal activity at pH8.5. Therefore, it is crucial to crystallize the active conformations of NhaA. Herein, we present a procedure for determining the structure of NhaA.
GPI anchors consist of three parts; protein, glycan and the phospholipids. The GPI anchored prote... more GPI anchors consist of three parts; protein, glycan and the phospholipids. The GPI anchored proteins work as cell surface hydrolases, protozoal antigens, adhesion molecules, mammalian antigens and involved in other significant cellular functions like dense packing of proteins on cell surface, increased protein mobility on cell surface , specific release from cell surface, control of exit from endoplasmic reticulum and toxin binding. Mutations in these proteins lead to Paroxysomal Nocturnal Haemogolbinuria and other disorders. This study was executed by combining comparative proteomics and phylogenetic approaches in order to address a cross family evolution of GPI anchor proteins from 23 different species. The results of revealed some unexplored specifics about the conserved domains GPI anchored proteins across different taxa of organisms. The results also demonstrated hierarchical assemblage based inconsistency in variation in the GPI anchored proteins
Advanced Science Letters, 2012
Scientific reports, Jan 29, 2016
The Na(+), Li(+)/H(+) antiporter of Escherichia coli (Ec-NhaA) maintains pH, Na(+) homeostasis in... more The Na(+), Li(+)/H(+) antiporter of Escherichia coli (Ec-NhaA) maintains pH, Na(+) homeostasis in enterobacteria. We used isothermal titration calorimetry to perform a detailed thermodynamic analysis of Li(+) binding to Ec-NhaA and several of its mutants. We found that, in line with the canonical alternative access mechanistic model of secondary transporters, Li(+)/H(+) binding to the antiporter is antagonistically coupled. Binding of Li(+) displaces 2 H(+) from the binding site. The process is enthalpically driven, the enthalpic gain just compensating for an entropic loss and the buffer-associated enthalpic changes dominate the overall free-energy change. Li(+) binding, H(+) release and antiporter activity were all affected to the same extent by mutations in the Li(+) binding site (D163E, D163N, D164N, D164E), while D133C changed the H(+)/Li(+) stoichiometry to 4. Most striking, however, was the mutation, A167P, which converted the Ec-NhaA antagonistic binding into synergistic bind...
Molecular Epidemiology Study of Mycobacterium Tuberculosis Complex, 2021
Tuberculosis (TB) is one of the deadly diseases in the present era caused by Mycobacterium tuberc... more Tuberculosis (TB) is one of the deadly diseases in the present era caused by Mycobacterium tuberculosis. Principally, this bacterium attacks the lungs, however, MTB Has been observed affecting any part of the human body including the kidney, spine, and brain. Drug-resistant progression and other associated properties of MTB become a major hurdle in drug discovery to fight against tuberculosis. Moreover, some of the challenging situations such as the low range of chemical agents, the time-consuming process of drug development, the shortage of predictive animal models, and inadequate information of the physicochemical evidence required for effective bacterial penetration, are additional hindrances for the pharmaceutical scientist. In the current chapter, we focus on challenges encountered during drug discovery and need to be overcome as M. tuberculosis has a substantial barrier in its lipid-containing cell wall to inhibit the influx of drugs which is the initial requirement of the dru...
Letters in Applied Microbiology, 2021
The interest in the working and functionality of the human gut microbiome has increased drastical... more The interest in the working and functionality of the human gut microbiome has increased drastically over the years. Though the existence of gut microbes has long been speculated for long over the last few decades, a lot of research has sprung up in studying and understanding the role of gut microbes in the human digestive tract. The microbes present in the gut are highly instrumental in maintaining the metabolism in the body. Further research is going on in this field to understand how gut microbes can be employed as potential sources of novel therapeutics, moreover, probiotics have also elucidated their significant place in this direction. As regards the clinical perspective, microbes can be engineered to afford defense mechanisms while interacting with foreign pathogenic bodies. More investigations in this field may assist us to evaluate and understand how these cells communicate with human cells and promote immune interactions. Here we elaborate on the possible implication of human gut microbiota into the immune system as well as explore the probiotics in the various human ailments. Comprehensive information on the human gut microbiome at the same platform may contribute affectively to our understanding of the human microbiome and possible mechanisms of associated human diseases.