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1.
J Mol Recognit ; 35(10): e2979, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35642097

RESUMO

Infections caused by the bacteria Enterococcus faecalis (also known as E. faecalis) are common in hospitals. This bacterium is resistant to a wide range of medicines and causes a variety of nosocomial infections. An increase in the number of infections caused by multidrug-resistant (MDR) bacteria is causing substantial economic and health issues around the world. Consequently, new therapeutic techniques to tackle the growing threat of E. faecalis infections must be developed as soon as possible. In this regard, we have targeted a protein that is regarded to be critical for the survival of bacteria in this experiment. Homoserine kinase (HSK) is a threonine metabolism enzyme that belongs to the GHMP kinase superfamily. It is a crucial enzyme in threonine metabolism. This enzyme is responsible for a critical step in the threonine biosynthesis pathway. Given the important function that E. faecalis Homoserine Kinase (ESK) plays in bacterial metabolism, we report here cloning, expression, purification and structural studies of E. faecalis HSK using homology modelling. In addition, we have reported on the model's molecular docking and Molecular Dynamic Stimulation (MD Stimulation) investigations to validate the results of the docking experiments. The results were promising. In silico investigations came up with the conclusion: pheniramine has good binding affinity for the E. faecalis HSK.


Assuntos
Enterococcus faecalis , Feniramina , Antibacterianos , Enterococcus faecalis/genética , Simulação de Acoplamento Molecular , Feniramina/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool) , Treonina/metabolismo
2.
Semin Cell Dev Biol ; 96: 77-90, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30951893

RESUMO

Phosphorus (P), an essential macronutrient, is pivotal for growth and development of plants. Availability of phosphate (Pi), the only assimilable P, is often suboptimal in rhizospheres. Pi deficiency triggers an array of spatiotemporal adaptive responses including the differential regulation of several transcription factors (TFs). Studies on MYB TF PHR1 in Arabidopsis thaliana (Arabidopsis) and its orthologs OsPHRs in Oryza sativa (rice) have provided empirical evidence of their significant roles in the maintenance of Pi homeostasis. Since the functional characterization of PHR1 in 2001, several other TFs have now been identified in these model plants. This raised a pertinent question whether there are any likely interactions across these TFs. Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system has provided an attractive paradigm for editing genome in plants. Here, we review the applications and challenges of this technique for genome editing of the TFs for deciphering the function and plausible interactions across them. This technology could thus provide a much-needed fillip towards engineering TFs for generating Pi use efficient plants for sustainable agriculture. Furthermore, we contemplate whether this technology could be a viable alternative to the controversial genetically modified (GM) rice or it may also eventually embroil into a limbo.


Assuntos
Sistemas CRISPR-Cas/genética , Edição de Genes , Homeostase/genética , Modelos Biológicos , Fosfatos/metabolismo , Plantas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Variação Genética/genética , Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo
3.
J Mol Recognit ; 34(6): e2886, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33393093

RESUMO

Entamoeba histolytica (Eh), a parasitic protozoan and the causative agent of invasive Amoebiasis, invade the host tissue through an effective secretory pathway. There are several lines of evidence suggesting that amoebic trophozoite pore-forming complex amoebapore and a large class of proteases enzymes including rhomboid proteases, cysteine proteases, and metalloproteases are implicated in host tissue invasion. For successful delivery of these molecules/cargos, trophozoites heavily rely on sorting machinery from the endoplasmic reticulum, Golgi to plasma membrane. Although, sole secretion machinery in E. histolytica is not characterized yet. Therefore, here our aim is to understand the properties of key molecules N-ethylmaleimide-sensitive fusion protein attached to protein receptors (SNAREs) in E. histolytica. SNAREs proteins are an important component of the membrane-trafficking machinery and have been associated in a range of processes including vesicle tethering, fusion as well as specificity of vesicular transport in all eukaryotic cells. SNARE proteins are architecturally simple, categorized by the presence of one copy of a homologous coiled-coil forming motif. However, the structural information and protein-protein interaction study of Eh-associated syntaxin proteins are still not known. Here, we characterize the syntaxin 1 like molecule and VAMP from Eh through physiochemical profiling, modeling, atomistic simulation, protein-protein interaction, and docking approaches on the proteins containing SNARE and synaptobrevin domain. The modeled structures and the critical residues recognized through protein interaction and docking study may provide better structural and functional insights into these proteins and may aid in the development of newer diagnostic assays.


Assuntos
Entamoeba histolytica/metabolismo , Mapas de Interação de Proteínas/fisiologia , Proteínas Qa-SNARE/metabolismo , Sequência de Aminoácidos , Membrana Celular/metabolismo , Membrana Celular/parasitologia , Células Eucarióticas/metabolismo , Células Eucarióticas/parasitologia , Canais Iônicos/metabolismo , Simulação de Acoplamento Molecular , Estudos Prospectivos , Proteínas de Protozoários/metabolismo , Proteínas R-SNARE/metabolismo , Proteínas SNARE/metabolismo
4.
J Mol Recognit ; 34(9): e2894, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33719110

RESUMO

Enterococcus faecalis (E. faecalis) is a Gram-positive coccoid, non-sporulating, facultative anaerobic, multidrug resistance bacterium responsible for almost 65% to 80% of all enterococcal nosocomial infections. It usually causes infective endocarditis, urinary tract and surgical wound infections. The increase in E. faecalis resistance to conventionally available antibiotic has rekindled intense interest in developing useful antibacterial drugs. In E. faecalis, diaminopimelate epimerase (DapF) is involved in the lysine biosynthetic pathway. The product of this pathway is precursors of peptidoglycan synthesis, which is a component of bacterial cell wall. Also, because mammals lack this enzyme, consequently E. faecalis diaminopimelate epimerase (EfDapF) represents a potential target for developing novel class of antibiotics. In this regard, we have successfully cloned, overexpressed the gene encoding DapF in BL-21(DE3) and purified with Ni-NTA Agarose resin. In addition to this, binding studies were performed using fluorescence spectroscopy in order to confirm the bindings of the identified lead compounds (acetaminophen and dexamethasone) with EfDapF. Docking studies revealed that acetaminophen found to make hydrogen bonds with Asn72 and Asn13 while dexamethasone interacted by forming hydrogen bonds with Asn205 and Glu223. Thus, biochemical studies indicated acetaminophen and dexamethasone, as potential inhibitors of EfDapF and eventually can reduce the catalytic activity of EfDapF.


Assuntos
Acetaminofen/farmacologia , Isomerases de Aminoácido/antagonistas & inibidores , Dexametasona/farmacologia , Enterococcus faecalis/enzimologia , Simulação de Acoplamento Molecular , Isomerases de Aminoácido/química , Isomerases de Aminoácido/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Sítios de Ligação , Reposicionamento de Medicamentos , Enterococcus faecalis/efeitos dos fármacos , Conformação Proteica
5.
Semin Cell Dev Biol ; 74: 123-132, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28903074

RESUMO

Availability of phosphate (Pi) is often limited in rhizospheres in different agroclimatic zones and adversely affects growth and development of plants. To circumvent this impasse, there is an urgent need and global consensus to develop Pi use efficient crops. To achieve this goal, it is essential to identify the molecular entities that exert regulatory influences on the sensing and signaling cascade governing Pi homeostasis. SIZ1 encodes a small ubiquitin-like modifier (SUMO E3) ligase, and plays a pivotal role in the post-translational SUMOylation of proteins. In this review, we discuss the reverse genetics approach conventionally used for providing circumstantial evidence towards the regulatory influences of SIZ1 on several morphophysiological and molecular traits that govern Pi homeostasis in taxonomically diverse Arabidopsis thaliana (Arabidopsis) and Oryza sativa (rice) model species. However, the efforts have been rather modest in identifying SUMO protein targets that play key roles in the maintenance of Pi homeostasis in these model plants contrary to the plethora of them now known in lower organisms and animals. Therefore, to predict the SIZ1-mediated SUMOylome involved in Pi homeostasis, the state-of-the-art high-throughput technologies often used for animals thus provide an attractive paradigm towards achieving the long-term goal of developing Pi use efficient crops.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Homeostase , Ligases/metabolismo , Oryza/metabolismo , Fosfatos/metabolismo , Sumoilação , Arabidopsis/química , Oryza/química
6.
J Mol Recognit ; 32(12): e2808, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31432591

RESUMO

The enteric protozoan parasite, Entamoeba histolytica (Eh), is the causative agent of amoebic dysentery and liver abscess in humans. It infects around 50 million people worldwide, which is a third general cause of death from parasitic diseases after malaria and schistosomiasis. The other prevalent form of the disease is Visceral leishmaniasis caused by Leishmania donovani which is a human blood parasite. On the other hand, the Toxoplasma gondii is an obligate intracellular protozoan parasite; it causes serious opportunistic infections in HIV-positive persons. The biological processes in all living organisms are mostly mediated by the proteins, and recognizing new target proteins and finding their function in pathogenesis will help in choosing better diagnostic markers. In eukaryotes, Rab protein plays a major role in pathogenesis. Rabs represent the largest branch in the Ras superfamily of GTPases. Among them, the Rab5 is important in the endocytosis and thus involved in pathogenesis. In this paper, we discussed the physiochemical profiling, modelling, and docking of the Rab5 protein from pathogenic species that is Entamoeba histolytica, Leishmania donovani, and Toxoplasma gondii. The modeled structures from this study and the key residues identified would give a better understanding of the three-dimensional structure and functional insights into these proteins and help in developing new drug targets.


Assuntos
Simulação por Computador , Entamoeba histolytica/metabolismo , Leishmania donovani/metabolismo , Toxoplasma/metabolismo , Proteínas rab5 de Ligação ao GTP/química , Motivos de Aminoácidos , Sequência de Aminoácidos , Ligação de Hidrogênio , Ligantes , Simulação de Acoplamento Molecular , Homologia Estrutural de Proteína , Proteínas rab5 de Ligação ao GTP/genética
7.
J Mol Recognit ; 32(11): e2802, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31353747

RESUMO

Enterococcus faecalis is a gram-positive, rod-shape bacteria responsible for around 65% to 80% of all enterococcal nosocomial infections. It is multidrug resistant (MDR) bacterium resistant to most of the first-line antibiotics. Due to the emergence of MDR strains, there is an urgent need to find novel targets to develop new antibacterial drugs against E. faecalis. In this regard, we have identified naphthoate synthase (1,4-dihydroxy-2-naphthoyl-CoA synthase, EC: 4.1.3.36; DHNS) as an anti-E. faecalis target, as it is an essential enzyme for menaquinone (vitamin K2 ) synthetic pathway in the bacterium. Thus, inhibiting naphtholate synthase may consequently inhibit the bacteria's growth. In this regard, we report here cloning, expression, purification, and preliminary structural studies of naphthoate synthase along with in silico modeling, molecular dynamic simulation of the model and docking studies of naphthoate synthase with quercetin, a plant alkaloid. Biochemical studies have indicated quercetin, a plant flavonoid as the potential lead compound to inhibit catalytic activity of EfDHNS. Quercetin binding has also been validated by spectrofluorimetric studies in order to confirm the bindings of the ligand compound with EfDHNS at ultralow concentrations. Reported studies may provide a base for structure-based drug development of antimicrobial compounds against E. faecalis.


Assuntos
Enterococcus faecalis/enzimologia , Inibidores Enzimáticos/farmacologia , Hidroliases/antagonistas & inibidores , Quercetina/farmacologia , Clonagem Molecular , Simulação por Computador , Cristalização , Enterococcus faecalis/efeitos dos fármacos , Hidroliases/química , Hidroliases/metabolismo , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Quercetina/química
8.
Biochem J ; 475(3): 547-560, 2018 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-29301982

RESUMO

Peptidyl-tRNA hydrolase (Pth) catalyzes the breakdown of peptidyl-tRNA into peptide and tRNA components. Pth from Acinetobacter baumannii (AbPth) was cloned, expressed, purified and crystallized in a native unbound (AbPth-N) state and in a bound state with the phosphate ion and cytosine arabinoside (cytarabine) (AbPth-C). Structures of AbPth-N and AbPth-C were determined at 1.36 and 1.10 Šresolutions, respectively. The structure of AbPth-N showed that the active site is filled with water molecules. In the structure of AbPth-C, a phosphate ion is present in the active site, while cytarabine is bound in a cleft which is located away from the catalytic site. The cytarabine-binding site is formed with residues: Gln19, Trp27, Glu30, Gln31, Lys152, Gln158 and Asp162. In the structure of AbPth-N, the side chains of two active-site residues, Asn70 and Asn116, were observed in two conformations. Upon binding of the phosphate ion in the active site, the side chains of both residues were ordered to single conformations. Since Trp27 is present at the cytarabine-binding site, the fluorescence studies were carried out which gave a dissociation constant (KD) of 3.3 ± 0.8 × 10-7 M for cytarabine. The binding studies using surface plasmon resonance gave a KD value of 3.7 ± 0.7 × 10-7 M. The bacterial inhibition studies using the agar diffusion method and the biofilm inhibition assay established the strong antimicrobial potential of cytarabine. It also indicated that cytarabine inhibited Gram-negative bacteria more profoundly when compared with Gram-positive bacteria in a dose-dependent manner. Cytarabine was also effective against the drug-resistant bacteria both alone as well as in combination with other antibiotics.


Assuntos
Acinetobacter baumannii/enzimologia , Biofilmes/efeitos dos fármacos , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/genética , Acinetobacter baumannii/química , Acinetobacter baumannii/genética , Antibacterianos/química , Antibacterianos/farmacologia , Sítios de Ligação , Hidrolases de Éster Carboxílico/farmacologia , Catálise , Domínio Catalítico , Cristalografia por Raios X , Citarabina/química , Escherichia coli/genética , Domínios Proteicos , RNA de Transferência/química , RNA de Transferência/genética , Aminoacil-RNA de Transferência/genética , Especificidade por Substrato , Propriedades de Superfície
9.
Biochim Biophys Acta ; 1844(7): 1279-88, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24768774

RESUMO

Peptidyl-tRNA hydrolase is an essential enzyme which acts as one of the rescue factors of the stalled ribosomes. It is an esterase that hydrolyzes the ester bond in the peptidyl-tRNA molecules, which are products of ribosome stalling. This enzyme is required for rapid clearing of the peptidyl-tRNAs, the accumulation of which in the cell leads to cell death. Over the recent years, it has been heralded as an attractive drug target for antimicrobial therapeutics. Two distinct classes of peptidyl-tRNA hydrolase, Pth and Pth2, have been identified in nature. This review gives an overview of the structural and functional aspects of Pth, along with its sequence and structural comparison among various species of bacteria. While the mode of binding of the substrate to Pth and the mechanism of hydrolysis are still speculated upon, the structure-based drug design using this protein as the target is still largely unexplored. This review focuses on the structural features of Pth, giving a direction to structure-based drug design on this protein.


Assuntos
Bactérias/enzimologia , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Hidrólise , Especificidade por Substrato
10.
ScientificWorldJournal ; 2014: 543195, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24696647

RESUMO

Pathogenesis related (PR) proteins are one of the major sources of plant derived allergens. These proteins are induced by the plants as a defense response system in stress conditions like microbial and insect infections, wounding, exposure to harsh chemicals, and atmospheric conditions. However, some plant tissues that are more exposed to environmental conditions like UV irradiation and insect or fungal attacks express these proteins constitutively. These proteins are mostly resistant to proteases and most of them show considerable stability at low pH. Many of these plant pathogenesis related proteins are found to act as food allergens, latex allergens, and pollen allergens. Proteins having similar amino acid sequences among the members of PR proteins may be responsible for cross-reactivity among allergens from diverse plants. This review analyzes the different pathogenesis related protein families that have been reported as allergens. Proteins of these families have been characterized in regard to their biological functions, amino acid sequence, and cross-reactivity. The three-dimensional structures of some of these allergens have also been evaluated to elucidate the antigenic determinants of these molecules and to explain the cross-reactivity among the various allergens.


Assuntos
Alérgenos/química , Hipersensibilidade Alimentar/imunologia , Proteínas de Plantas/química , Proteínas de Plantas/fisiologia , Sequência de Aminoácidos , Reações Cruzadas , Humanos , Dados de Sequência Molecular , Plantas Geneticamente Modificadas , Conformação Proteica
11.
Curr Pharm Des ; 30(3): 161-168, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38243948

RESUMO

Sepsis is a complex clinical condition and a leading cause of death worldwide. During Sepsis, there is a derailment in the host response to infection, which can progress to severe sepsis and multiple organ dysfunction or failure, which leads to death. Free radicals, including reactive oxygen species (ROS) generated predominantly in mitochondria, are one of the key players in impairing normal organ function in sepsis. ROS contributing to oxidative stress has been reported to be the main culprit in the injury of the lung, heart, liver, kidney, gastrointestinal, and other organs. Here in the present review, we describe the generation, and essential properties of various types of ROS, their effect on macromolecules, and their role in mitochondrial dysfunction. Furthermore, the mechanism involved in the ROS-mediated pathogenesis of sepsis-induced organ dysfunction has also been discussed.


Assuntos
Doenças Mitocondriais , Sepse , Humanos , Espécies Reativas de Oxigênio , Insuficiência de Múltiplos Órgãos , Radicais Livres , Sepse/patologia , Estresse Oxidativo
12.
Artigo em Inglês | MEDLINE | ID: mdl-23722845

RESUMO

Acinetobacter baumannii is a virulent pathogenic bacterium that is resistant to most currently available antibiotics. Therefore, the design of drugs for the treatment of infections caused by A. baumannii is urgently required. Dihydrodipicolinate reductase (DHDPR) is an important enzyme which is involved in the biosynthetic pathway that leads to the production of L-lysine in bacteria. In order to design potent inhibitors against this enzyme, its detailed three-dimensional structure is required. DHDPR from A. baumannii (AbDHDPR) has been cloned, expressed, purified and crystallized. Here, the preliminary X-ray crystallographic data of AbDHDPR are reported. The crystals were grown using the hanging-drop vapour-diffusion method with PEG 3350 as the precipitating agent The crystals belonged to the orthorhombic space group P222, with unit-cell parameters a = 80.0, b = 100.8, c = 147.6 Å, and contained four molecules in the asymmetric unit. The complete structure determination of AbDHDPR is in progress.


Assuntos
Clonagem Molecular , Di-Hidrodipicolinato Redutase/química , Di-Hidrodipicolinato Redutase/genética , Regulação Enzimológica da Expressão Gênica , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Clonagem Molecular/métodos , Cristalização , Cristalografia por Raios X , Di-Hidrodipicolinato Redutase/isolamento & purificação , Dados de Sequência Molecular
13.
Int Immunopharmacol ; 118: 110100, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37011501

RESUMO

Entamoeba histolytica (Eh), a microaerophilic parasite, causes deadly enteric infections that result in Amoebiasis. Every year, the count of invasive infections reaches 50 million approximately and 40,000 to 1,00,000 deaths occurring due to amoebiasis are reported globally. Profound inflammation is the hallmark of severe amoebiasis which is facilitated by immune first defenders, neutrophils. Due to size incompatibility, neutrophils are unable to phagocytose Eh and thus, came up with the miraculous antiparasitic mechanism of neutrophil extracellular traps (NETs). This review provides an in-depth analysis of NETosis induced by Eh including the antigens involved in the recognition of Eh and the biochemistry of NET formation. Additionally, it underscores its novelty by describing the dual role of NETs in amoebiasis where it acts as a double-edged sword in terms of both clearing and exacerbating amoebiasis. It also provides a comprehensive account of the virulence factors discovered to date that are implicated directly and indirectly in the pathophysiology of Eh infections through the lens of NETs and can be interesting drug targets.


Assuntos
Entamoeba histolytica , Entamebíase , Armadilhas Extracelulares , Entamebíase/tratamento farmacológico , Entamebíase/epidemiologia , Entamebíase/fisiopatologia , Neutrófilos , Sistemas de Liberação de Medicamentos , Humanos , Antígenos Nucleares
14.
Diagnostics (Basel) ; 13(2)2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36673087

RESUMO

Sepsis is one of the deadliest disorders in the new century due to specific limitations in early and differential diagnosis. Moreover, antimicrobial resistance (AMR) is becoming the dominant threat to human health globally. The only way to encounter the spread and emergence of AMR is through the active detection and identification of the pathogen along with the quantification of resistance. For better management of such disease, there is an essential requirement to approach many suitable diagnostic techniques for the proper administration of antibiotics and elimination of these infectious diseases. The current method employed for the diagnosis of sepsis relies on the conventional culture of blood suspected infection. However, this method is more time consuming and generates results that are false negative in the case of antibiotic pretreated samples as well as slow-growing microbes. In comparison to the conventional method, modern methods are capable of analyzing blood samples, obtaining accurate results from the suspicious patient of sepsis, and giving all the necessary information to identify the pathogens as well as AMR in a short period. The present review is intended to highlight the culture shift from conventional to modern and advanced technologies including their limitations for the proper and prompt diagnosing of bloodstream infections and AMR detection.

15.
Microbiol Res ; 261: 127061, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35605309

RESUMO

The regulation of the activity of proteases by endogenous inhibitors is a common trend in almost all forms of life. Here, we review the endogenous inhibitors of cysteine proteases of three major pathogenic parasitic protozoa. The review focuses on members of the genus Plasmodium, Entamoeba, and Leishmania. Research in this domain has revealed the presence of only chagasin-like inhibitors of cysteine proteases that house a ß-barrel immunoglobulin-fold and inhibit the target proteases using a 3-loop inhibitory mechanism in these pathogens. Inhibitors of cysteine proteases are highly evolvable enzymes that target a broad spectrum of pathogenic cysteine proteases with a proclivity for those involved in host-parasite interactions. A common trend reflects a limited sequence homology between cysteine proteases and their inhibitors. The inhibitors are also known to participate in other housekeeping functions of the parasites. Generalizations about their roles are thus best avoided. In this review, the reader will find comprehensive information on the cellular localization of inhibitors of cysteine proteases, their structure, function, and the associated mechanisms of action. The reader will also find a thorough analysis of the role of these inhibitors in parasite pathology and the common trends interlinking them with parasite biology and evolution.


Assuntos
Cisteína Proteases , Parasitos , Sequência de Aminoácidos , Animais , Inibidores de Cisteína Proteinase/farmacologia , Proteínas de Protozoários
16.
Curr Protein Pept Sci ; 23(4): 248-263, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35619261

RESUMO

Enterococcus faecalis (E. faecalis) is an opportunistic multidrug-resistant (MDR) pathogen found in the guts of humans and farmed animals. Due to the occurrence of (MDR) strain there is an urgent need to look for an alternative treatment approach. E. faecalis is a Gram-positive bacterium, which is among the most prevalent multidrug resistant hospital pathogens. Its ability to develop quorum sensing (QS) mediated biofilm formation further exacerbates the pathogenicity and triggers lifethreatening infections. Therefore, developing a suitable remedy for curing E. faecalis mediated enterococcal infections is an arduous task. Several putative virulence factors and proteins are involved in the development of biofilms in E. faecalis. Such proteins often play important roles in virulence, disease, and colonization by pathogens. The elucidation of the structure-function relationship of such protein drug targets and the interacting compounds could provide an attractive paradigm towards developing structure-based drugs against E. faecalis. This review provides a comprehensive overview of the current status, enigmas that warrant further studies, and the prospects toward alleviating the antibiotic resistance in E. faecalis. Specifically, the role of biofilm and quorum sensing (QS) in the emergence of MDR strains had been elaborated along with the importance of the protein drug targets involved in both the processes.


Assuntos
Biofilmes , Farmacorresistência Bacteriana Múltipla , Enterococcus faecalis , Percepção de Quorum , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Proteínas de Bactérias/metabolismo , Enterococcus faecalis/efeitos dos fármacos , Virulência , Fatores de Virulência/genética
17.
Curr Protein Pept Sci ; 23(4): 211-225, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35598240

RESUMO

S-adenosylhomocysteine nucleosidase (MTAN) is a protein that plays a crucial role in several pathways of bacteria that are essential for its survival and pathogenesis. In addition to the role of MTAN in methyl-transfer reactions, methionine biosynthesis, and polyamine synthesis, MTAN is also involved in bacterial quorum sensing (QS). In QS, chemical signaling autoinducer (AI) secreted by bacteria assists cell to cell communication and is regulated in a cell density-dependent manner. They play a significant role in the formation of bacterial biofilm. MTAN plays a major role in the synthesis of these autoinducers. Signaling molecules secreted by bacteria, i.e., AI-1 are recognized as acylated homoserine lactones (AHL) that function as signaling molecules within bacteria. QS enables bacteria to establish physical interactions leading to biofilm formation. The formation of biofilm is a primary reason for the development of multidrug-resistant properties in pathogenic bacteria like Enterococcus faecalis (E. faecalis). In this regard, inhibition of E. faecalis MTAN (EfMTAN) will block the QS and alter the bacterial biofilm formation. In addition to this, it will also block methionine biosynthesis and many other critical metabolic processes. It should also be noted that inhibition of EfMTAN will not have any effect on human beings as this enzyme is not present in humans. This review provides a comprehensive overview of the structural-functional relationship of MTAN. We have also highlighted the current status, enigmas that warrant further studies, and the prospects for identifying potential inhibitors of EfMTAN for the treatment of E. faecalis infections. In addition to this, we have also reported structural studies of EfMTAN using homology modeling and highlighted the putative binding sites of the protein.


Assuntos
N-Glicosil Hidrolases , Percepção de Quorum , Bactérias/metabolismo , Biofilmes , Homocisteína , Humanos , Metionina , N-Glicosil Hidrolases/química , N-Glicosil Hidrolases/metabolismo
18.
Biomed Res Int ; 2022: 5058121, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35309178

RESUMO

Chronic obstructive pulmonary disease (COPD) is pulmonary emphysema characterized by blockage in the airflow resulting in the long-term breathing problem, hence a major cause of mortality worldwide. Excessive generation of free radicals and the development of chronic inflammation are the major two episodes underlying the pathogenesis of COPD. Currently used drugs targeting these episodes including anti-inflammatory, antioxidants, and corticosteroids are unsafe, require high doses, and pose serious side effects. Nanomaterial-conjugated drugs have shown promising therapeutic potential against different respiratory diseases as they are required in small quantities which lower overall treatment costs and can be effectively targeted to diseased tissue microenvironment hence having minimal side effects. Poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) are safe as their breakdown products are easily metabolized in the body. Drugs loaded on the PLGA NPs have been shown to be promising agents as anticancer, antimicrobial, antioxidants, and anti-inflammatory. Surface modification of PLGA NPs can further improve their mechanical properties, drug loading potential, and pharmacological activities. In the present review, we have presented a brief insight into the pathophysiological mechanism underlying COPD and highlighted the role, potential, and current status of PLGA NPs loaded with drugs in the therapy of COPD.


Assuntos
Nanopartículas , Doença Pulmonar Obstrutiva Crônica , Antioxidantes/uso terapêutico , Portadores de Fármacos , Glicóis , Humanos , Ácido Láctico , Nanopartículas/uso terapêutico , Ácido Poliglicólico , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico
19.
Vaccines (Basel) ; 10(10)2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36298439

RESUMO

Oxidative stress resulting from the disproportion of oxidants and antioxidants contributes to both physiological and pathological conditions in sepsis. To combat this, the antioxidant defense system comes into the picture, which contributes to limiting the amount of reactive oxygen species (ROS) leading to the reduction of oxidative stress. However, a strong relationship has been found between scavengers of ROS and antioxidants in preclinical in vitro and in vivo models. ROS is widely believed to cause human pathology most specifically in sepsis, where a small increase in ROS levels activates signaling pathways to initiate biological processes. An inclusive understanding of the effects of ROS scavenging in cellular antioxidant signaling is essentially lacking in sepsis. This review compiles the mechanisms of ROS scavenging as well as oxidative damage in sepsis, as well as antioxidants as a potent therapeutic. Direct interaction between ROS and cellular pathways greatly affects sepsis, but such interaction does not provide the explanation behind diverse biological outcomes. Animal models of sepsis and a number of clinical trials with septic patients exploring the efficiency of antioxidants in sepsis are reviewed. In line with this, both enzymatic and non-enzymatic antioxidants were effective, and results from recent studies are promising. The usage of these potent antioxidants in sepsis patients would greatly impact the field of medicine.

20.
Vaccines (Basel) ; 10(10)2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-36298513

RESUMO

Previous reports from our lab have documented dysregulated host inflammatory reactions in response to bacterial infections in sepsis. Both Gram-negative bacteria (GNB) and Gram-positive bacteria (GPB) play a significant role in the development and progression of sepsis by releasing several virulence factors. During sepsis, host cells produce a range of inflammatory responses including inducible nitric oxide synthase (iNOS) expression, nitrite generation, neutrophil extracellular traps (NETs) release, and pro-inflammatory cytokines production. The current study was conducted to discern the differences in host inflammatory reactions in response to both Escherichia coli and Staphylococcus aureus along with the organ dysfunction parameters in patients of sepsis. We examined 60 ICU sepsis patients identified based on the Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA II) scores. Pathogen identification was carried out using culture-based methods and gene-specific primers by real-time polymerase chain reaction (RT-PCR). Samples of blood from healthy volunteers were spiked with E. coli (GNB) and S. aureus (GPB). The incidence of NETs formation, iNOS expression, total nitrite content, and pro-inflammatory cytokine level was estimated. Prevalence of E. coli, A. baumannii (both GNB), S. aureus, and Enterococcus faecalis (both GPB) was found in sepsis patients. Augmented levels of inflammatory mediators including iNOS expression, total nitrite, the incidence of NETs, and proinflammatory cytokines, during spiking, were found in response to S. aureus infections in comparison with E. coli infections. These inflammatory mediators were found to be positively correlated with organ dysfunction in both GN and GP infections in sepsis patients. Augmented host inflammatory response was generated in S. aureus infections as compared with E. coli.

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