2005 Alfred Bader Award Lecture Diaminopimelate and lysine biosynthesis - An antimicrobial target in bacteria

2006 ◽  
Vol 84 (10) ◽  
pp. 1197-1207 ◽  
Author(s):  
John C Vederas
Keyword(s):  
Active Site ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Crystallographic Analysis ◽  
Enzyme Mechanism ◽  
Lysine Biosynthesis ◽  
Pimelic Acid ◽  
Enzyme Active Site ◽  
Antibiotic Development ◽  
Lipid Ii

The development of bacterial resistance to current antibiotic therapy has stimulated the search for novel antimicrobial agents. The essential peptidoglycan cell wall layer in bacteria is the site of action of many current drugs, such as β-lactams and vancomycin. It is also a target for a number of very potent bacterially produced antibiotic peptides, such as nisin A and lacticin 3147, both of which are highly posttranslationally modified lantibiotics that act by binding to lipid II, the peptidoglycan precursor. Another set of potential targets for antibiotic development are the bacterial enzymes that make precursors for lipid II and peptidoglycan, for example, those in the pathway to diamino pimelic acid (DAP) and its metabolic product, L-lysine. Among these, DAP epimerase is a unique nonpyridoxal phosphate (PLP) dependent enzyme that appears to use two active site thiols (Cys73 and Cys217) as a base and an acid to depro tonate the α-hydrogen of LL-DAP or meso-DAP from one side and reprotonate from the other. This process cannot be easily duplicated in the absence of the enzyme. A primary goal of our work was to generate inhibitors of DAP epi merase that would accurately mimic the natural substrates (meso-DAP and LL-DAP) in the enzyme active site and, through crystallographic analysis, provide insight into mechanism and substrate specificity. A series of aziridine-containing DAP analogs were chemically synthesized and tested as inhibitors of DAP epimerase from Haemophilus influenzae. Two diastereomers of 2-(4-amino-4-carboxybutyl)aziridine-2-carboxylic acid (AziDAP) act as rapid irreversible inactivators of DAP epimerase; the AziDAP analog of LL-DAP reacts selectively with the sulfhydryl of Cys73, whereas the corresponding analog of meso-DAP reacts with Cys217. AziDAP isomers are too unstable to be useful antibiotics. However, mass spectral and X-ray crystallographic analyses of the inactivated enzymes confirm that the thiol attacks the methylene group of the aziridine with concomitant ring opening to give a DAP analog bound in the active site. Further crystallographic analyses should yield useful mechanistic insights.Key words: enzyme mechanism, enzyme inhibition, antibiotics, aziridines, amino acids.

scholarly journals The Lactococcal dgkB (yecE) and dxsA Genes for Lipid Metabolism Are Involved in the Resistance to Cell Envelope-Acting Antimicrobials

2021 ◽  
Vol 22 (3) ◽  
pp. 1014
Author(s):  
Aleksandra Tymoszewska ◽  
Tamara Aleksandrzak-Piekarczyk
Keyword(s):  
Antimicrobial Peptides ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Cytoplasmic Membrane ◽  
Cross Resistance ◽  
Resistant Bacteria ◽  
Membrane Targeting ◽  
Nucleotide Polymorphisms ◽  
Next Generation ◽  
Lipid Ii

The emergence of antibiotic-resistant bacteria led to an urgent need for next-generation antimicrobial agents with novel mechanisms of action. The use of positively charged antimicrobial peptides that target cytoplasmic membrane is an especially promising strategy since essential functions and the conserved structure of the membrane hinder the development of bacterial resistance. Aureocin A53- and enterocin L50-like bacteriocins are highly cationic, membrane-targeting antimicrobial peptides that have potential as next-generation antibiotics. However, the mechanisms of resistance to these bacteriocins and cross-resistance against antibiotics must be examined before application to ensure their safe use. Here, in the model bacterium Lactococcus lactis, we studied the development of resistance to selected aureocin A53- and enterocin L50-like bacteriocins and its correlation with antibiotics. First, to generate spontaneous resistant mutants, L.lactis was exposed to bacteriocin BHT-B. Sequencing of their genomes revealed single nucleotide polymorphisms (SNPs) in the dgkB (yecE) and dxsA genes encoding diacylglycerol kinase and 1-deoxy-D-xylulose 5-phosphate synthase, respectively. Then, selected mutants underwent susceptibility tests with a wide array of bacteriocins and antibiotics. The highest alterations in the sensitivity of studied mutants were seen in the presence of cytoplasmic membrane targeting bacteriocins (K411, Ent7, EntL50, WelM, SalC, nisin) and antibiotics (daptomycin and gramicidin) as well as lipid II cycle-blocking bacteriocins (nisin and Lcn972) and antibiotics (bacitracin). Interestingly, decreased via the SNPs accumulation sensitivity to membrane-active bacteriocins and antibiotics resulted in the concurrently increased vulnerability to bacitracin, carbenicillin, or chlortetracycline. It is suspected that SNPs may result in alterations to the efficiency of the nascent enzymes rather than a total loss of their function as neither deletion nor overexpression of dxsA restored the phenotype observed in spontaneous mutants.

On the mechanism of phosphoenolpyruvate synthetase (PEPs) and its inhibition by sodium fluoride: potential magnesium and aluminum fluoride complexes of phosphoryl transfer

2015 ◽  
Vol 93 (3) ◽  
pp. 236-240 ◽  
Author(s):  
Nicole E. McCormick ◽  
David L. Jakeman
Keyword(s):  
Sodium Fluoride ◽  
Active Site ◽  
Carbon Sources ◽  
Indirect Evidence ◽  
Intermediate Formation ◽  
Phosphoryl Transfer ◽  
Metal Fluoride ◽  
Enzyme Active Site ◽  
Antibiotic Development ◽  
Fluoride Complexes

Phosphoenolpyruvate synthase (PEPs) catalyzes the conversion of pyruvate to phosphoenolpyruvate (PEP) using a two-step mechanism invoking a phosphorylated-His intermediate. Formation of PEP is an initial step in gluconeogenesis, and PEPs is essential for growth of Escherichia coli on 3-carbon sources such as pyruvate. The production of PEPs has also been linked to bacterial virulence and antibiotic resistance. As such, PEPs is of interest as a target for antibiotic development, and initial investigations of PEPs have indicated inhibition by sodium fluoride. Similar inhibition has been observed in a variety of phospho-transfer enzymes through the formation of metal fluoride complexes within the active site. Herein we quantify the inhibitory capacity of sodium fluoride through a coupled spectrophotometric assay. The observed inhibition provides indirect evidence for the formation of a MgF3−complex within the enzyme active site and insight into the phospho-transfer mechanism of PEPs. The effect of AlCl3on PEPs enzyme activity was also assessed and found to decrease substrate binding and turnover.

scholarly journals Topical Nano Clove/Thyme Gel against Genetically Identified Clinical Skin Isolates: In Vivo Targeting Behavioral Alteration and IGF-1/pFOXO-1/PPAR γ Cues

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5608
Author(s):  
Jilan A. Nazeam ◽  
Ghada M. Ragab ◽  
Amira A. El-Gazar ◽  
Shereen S. El-Mancy ◽  
Lina Jamil ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Acne Vulgaris ◽  
In Vivo Model ◽  
Biofilm Inhibition ◽  
Behavioral Alteration ◽  
Antibiotic Development ◽  
Ppar Γ

Antimicrobial resistance is a dramatic global threat; however, the slow progress of new antibiotic development has impeded the identification of viable alternative strategies. Natural antioxidant-based antibacterial approaches may provide potent therapeutic abilities to effectively block resistance microbes’ pathways. While essential oils (EOs) have been reported as antimicrobial agents, its application is still limited ascribed to its low solubility and stability characters; additionally, the related biomolecular mechanisms are not fully understood. Hence, the study aimed to develop a nano-gel natural preparation with multiple molecular mechanisms that could combat bacterial resistance in an acne vulgaris model. A nano-emulgel of thyme/clove EOs (NEG8) was designed, standardized, and its antimicrobial activity was screened in vitro and in vivo against genetically identified skin bacterial clinical isolates (Pseudomonas stutzeri, Enterococcus faecium and Bacillus thuringiensis). As per our findings, NEG8 exhibited bacteriostatic and potent biofilm inhibition activities. An in vivo model was also established using the commercially available therapeutic, adapalene in contra genetically identified microorganism. Improvement in rat behavior was reported for the first time and NEG8 abated the dermal contents/protein expression of IGF-1, TGF-β/collagen, Wnt/β-catenin, JAK2/STAT-3, NE, 5-HT, and the inflammatory markers; p(Ser536) NF-κBp65, TLR-2, and IL-6. Moreover, the level of dopamine, protective anti-inflammatory cytokine, IL-10 and PPAR-γ protein were enhanced, also the skin histological structures were improved. Thus, NEG8 could be a future potential topical clinical alternate to synthetic agents, with dual merit mechanism as bacteriostatic antibiotic action and non-antibiotic microbial pathway inhibitor.

Forecast of Antibiotic Development in an Era of Increasing Bacterial Resistance

2008 ◽  
Vol 21 (5) ◽  
pp. 313-318 ◽  
Author(s):  
Edward H. Eiland ◽  
Derek Gatlin
Keyword(s):  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Control Strategies ◽  
Antibiotic Use ◽  
Diagnostic Techniques ◽  
Chronic Illnesses ◽  
Antibiotic Development ◽  
The Public ◽  
Multiple Factors ◽  
Governmental Funding

Over the last decade there has been a decreased number of novel antimicrobial agents introduced to the market due to multiple factors including reduced governmental funding, marginal research and development interest by the pharmaceutical industry, lack of return on investment relative to medications used for chronic illnesses, and spiking microbial resistance trends. In an effort to most judiciously use the available armamentarium of anti-infectives available, many hospitals are implementing stewardship programs to re-direct inappropriate antibiotic use, which is estimated to account for up to 50% of all antibiotics prescribed. These efforts make it increasingly evident that the best defense against inappropriate antimicrobial use is accurate diagnosis of infectious diseases. Both the public and federal government must recognize the need for new and improved antimicrobials, as well as augmented infection control strategies and diagnostic techniques, to appropriately aid in the facilitation of bacterial control or eradication.

scholarly journals Structure ofStaphylococcus aureusadenylosuccinate lyase (PurB) and assessment of its potential as a target for structure-based inhibitor discovery

2010 ◽  
Vol 66 (8) ◽  
pp. 881-888 ◽  
Author(s):  
Paul K. Fyfe ◽  
Alice Dawson ◽  
Marie-Theres Hutchison ◽  
Scott Cameron ◽  
William N. Hunter
Keyword(s):  
Active Site ◽  
Active Sites ◽  
Bacterial Pathogen ◽  
Enzyme Mechanism ◽  
Enzyme Active Site ◽  
Adenylosuccinate Lyase ◽  
Medium Resolution ◽  
Inhibitor Discovery ◽  
Species Specific ◽  
Distinct Subunit

The medium-resolution structure of adenylosuccinate lyase (PurB) from the bacterial pathogenStaphylococcus aureusin complex with AMP is presented. Oxalate, which is likely to be an artifact of crystallization, has been modelled in the active site and occupies a position close to that where succinate is observed in orthologous structures. PurB catalyzes reactions that support the provision of purines and the control of AMP/fumarate levels. As such, the enzyme is predicted to be essential for the survival ofS. aureusand to be a potential therapeutic target. Comparisons of this pathogen PurB with the enzyme fromEscherichia coliare presented to allow discussion concerning the enzyme mechanism. Comparisons with human PurB suggest that the close similarity of the active sites would make it difficult to identify species-specific inhibitors for this enyme. However, there are differences in the way that the subunits are assembled into dimers. The distinct subunit–subunit interfaces may provide a potential area to target by exploiting the observation that creation of the enzyme active site is dependent on oligomerization.

scholarly journals Cleavage of nicotinamide adenine dinucleotide by the ribosome-inactivating protein fromMomordica charantia

2015 ◽  
Vol 71 (9) ◽  
pp. 1152-1155 ◽  
Author(s):  
M. Vinkovic ◽  
G. Dunn ◽  
G. E. Wood ◽  
J. Husain ◽  
S. P. Wood ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
Active Site ◽  
Nicotinamide Adenine Dinucleotide ◽  
Membered Ring ◽  
Enzyme Mechanism ◽  
X Ray Diffraction ◽  
Ribosome Inactivating Protein ◽  
X Ray ◽  
Enzyme Active Site

The interaction of momordin, a type 1 ribosome-inactivating protein fromMomordica charantia, with NADP+and NADPH has been investigated by X-ray diffraction analysis of complexes generated by co-crystallization and crystal soaking. It is known that the proteins of this family readily cleave the adenine–ribose bond of adenosine and related nucleotides in the crystal, leaving the product, adenine, bound to the enzyme active site. Surprisingly, the nicotinamide–ribose bond of oxidized NADP+is cleaved, leaving nicotinamide bound in the active site in the same position but in a slightly different orientation to that of the five-membered ring of adenine. No binding or cleavage of NADPH was observed at pH 7.4 in these experiments. These observations are in accord with current views of the enzyme mechanism and may contribute to ongoing searches for effective inhibitors.

Synthesis, evaluation, and crystallographic analysis of L-371,912: A potent and selective active-site thrombin inhibitor

1997 ◽  
Vol 7 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Terry A. Lyle ◽  
Zhongguo Chen ◽  
Sandra D. Appleby ◽  
Roger M. Freidinger ◽  
Stephen J. Gardell ◽  
...  
Keyword(s):  
Active Site ◽  
Crystallographic Analysis ◽  
Thrombin Inhibitor

scholarly journals Conformation-Specific Inhibitory Anti-MMP-7 Monoclonal Antibody Sensitizes Pancreatic Ductal Adenocarcinoma Cells to Chemotherapeutic Cell Kill

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1679
Author(s):  
Vishnu Mohan ◽  
Jean P. Gaffney ◽  
Inna Solomonov ◽  
Maxim Levin ◽  
Mordehay Klepfish ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Active Site ◽  
Drug Targets ◽  
Fas Ligand ◽  
Specific Activity ◽  
Matrix Metalloproteases ◽  
Ductal Adenocarcinoma ◽  
Enzyme Active Site ◽  
Induced Apoptosis

Matrix metalloproteases (MMPs) undergo post-translational modifications including pro-domain shedding. The activated forms of these enzymes are effective drug targets, but generating potent biological inhibitors against them remains challenging. We report the generation of anti-MMP-7 inhibitory monoclonal antibody (GSM-192), using an alternating immunization strategy with an active site mimicry antigen and the activated enzyme. Our protocol yielded highly selective anti-MMP-7 monoclonal antibody, which specifically inhibits MMP-7′s enzyme activity with high affinity (IC50 = 132 ± 10 nM). The atomic model of the MMP-7-GSM-192 Fab complex exhibited antibody binding to unique epitopes at the rim of the enzyme active site, sterically preventing entry of substrates into the catalytic cleft. In human PDAC biopsies, tissue staining with GSM-192 showed characteristic spatial distribution of activated MMP-7. Treatment with GSM-192 in vitro induced apoptosis via stabilization of cell surface Fas ligand and retarded cell migration. Co-treatment with GSM-192 and chemotherapeutics, gemcitabine and oxaliplatin elicited a synergistic effect. Our data illustrate the advantage of precisely targeting catalytic MMP-7 mediated disease specific activity.

scholarly journals Toward the Identification of Potential α-Ketoamide Covalent Inhibitors for SARS-CoV-2 Main Protease: Fragment-Based Drug Design and MM-PBSA Calculations

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1004
Author(s):  
Mahmoud A. El Hassab ◽  
Mohamed Fares ◽  
Mohammed K. Abdel-Hamid Amin ◽  
Sara T. Al-Rashood ◽  
Amal Alharbi ◽  
...  
Keyword(s):  
Drug Design ◽  
Active Site ◽  
Binding Free Energy ◽  
Stable Complex ◽  
Active Site Residues ◽  
Structure Based Drug Design ◽  
Enzyme Active Site ◽  
Potential Inhibitor ◽  
Main Protease ◽  
Covalent Docking

Since December 2019, the world has been facing the outbreak of the SARS-CoV-2 pandemic that has infected more than 149 million and killed 3.1 million people by 27 April 2021, according to WHO statistics. Safety measures and precautions taken by many countries seem insufficient, especially with no specific approved drugs against the virus. This has created an urgent need to fast track the development of new medication against the virus in order to alleviate the problem and meet public expectations. The SARS-CoV-2 3CL main protease (Mpro) is one of the most attractive targets in the virus life cycle, which is responsible for the processing of the viral polyprotein and is a key for the ribosomal translation of the SARS-CoV-2 genome. In this work, we targeted this enzyme through a structure-based drug design (SBDD) protocol, which aimed at the design of a new potential inhibitor for Mpro. The protocol involves three major steps: fragment-based drug design (FBDD), covalent docking and molecular dynamics (MD) simulation with the calculation of the designed molecule binding free energy at a high level of theory. The FBDD step identified five molecular fragments, which were linked via a suitable carbon linker, to construct our designed compound RMH148. The mode of binding and initial interactions between RMH148 and the enzyme active site was established in the second step of our protocol via covalent docking. The final step involved the use of MD simulations to test for the stability of the docked RMH148 into the Mpro active site and included precise calculations for potential interactions with active site residues and binding free energies. The results introduced RMH148 as a potential inhibitor for the SARS-CoV-2 Mpro enzyme, which was able to achieve various interactions with the enzyme and forms a highly stable complex at the active site even better than the co-crystalized reference.

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