Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

QM/MM modeling of class A β-lactamases reveals distinct acylation pathways for ampicillin and cefalexin.

ABSTRACT: Efficient mechanism-based design of antibiotics that are not susceptible to β-lactamases is hindered by the lack of comprehensive knowledge on the energetic landscapes for the hydrolysis of various β-lactams. Herein, we adopted efficient quantum mechanics/molecular mechanics simulations to explore the acylation reaction catalyzed by CTX-M-44 (Toho-1) β-lactamase. We show that the catalytic pathways for β-lactam hydrolysis are correlated to substrate scaffolds: using Glu166 as the only general base for acylation is viable for ampicillin but prohibitive for cefalexin. The present computational workflow provides quantitative insights to facilitate the optimization of future β-lactam antibiotics.

SUBMITTER: Song Z

PROVIDER: S-EPMC8613693 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

QM/MM modeling of class A β-lactamases reveals distinct acylation pathways for ampicillin and cefalexin.

Song Zilin Z Trozzi Francesco F Palzkill Timothy T Tao Peng P

Organic & biomolecular chemistry 20211103 42

Efficient mechanism-based design of antibiotics that are not susceptible to β-lactamases is hindered by the lack of comprehensive knowledge on the energetic landscapes for the hydrolysis of various β-lactams. Herein, we adopted efficient quantum mechanics/molecular mechanics simulations to explore the acylation reaction catalyzed by CTX-M-44 (Toho-1) β-lactamase. We show that the catalytic pathways for β-lactam hydrolysis are correlated to substrate scaffolds: using Glu166 as the only general ba ...[more]

PMID: 34647114

Similar Datasets

QM/MM Simulations Reveal the Determinants of Carbapenemase Activity in Class A β-Lactamases.

Project description:β-lactam antibiotic resistance in Gram-negative bacteria, primarily caused by β-lactamase enzymes that hydrolyze the β-lactam ring, has become a serious clinical problem. Carbapenems were formerly considered "last resort" antibiotics because they escaped breakdown by most β-lactamases, due to slow deacylation of the acyl-enzyme intermediate. However, an increasing number of Gram-negative bacteria now produce β-lactamases with carbapenemase activity: these efficiently hydrolyze the carbapenem β-lactam ring, severely limiting the treatment of some bacterial infections. Here, we use quantum mechanics/molecular mechanics (QM/MM) simulations of the deacylation reactions of acyl-enzyme complexes of eight β-lactamases of class A (the most widely distributed β-lactamase group) with the carbapenem meropenem to investigate differences between those inhibited by carbapenems (TEM-1, SHV-1, BlaC, and CTX-M-16) and those that hydrolyze them (SFC-1, KPC-2, NMC-A, and SME-1). QM/MM molecular dynamics simulations confirm the two enzyme groups to differ in the preferred acyl-enzyme orientation: carbapenem-inhibited enzymes favor hydrogen bonding of the carbapenem hydroxyethyl group to deacylating water (DW). QM/MM simulations of deacylation give activation free energies in good agreement with experimental hydrolysis rates, correctly distinguishing carbapenemases. For the carbapenem-inhibited enzymes, free energies for deacylation are significantly higher than for the carbapenemases, even when the hydroxyethyl group was restrained to prevent interaction with the DW. Analysis of these simulations, and additional simulations of mutant enzymes, shows how factors including the hydroxyethyl orientation, the active site volume, and architecture (conformations of Asn170 and Asn132; organization of the oxyanion hole; and the Cys69-Cys238 disulfide bond) collectively determine catalytic efficiency toward carbapenems.

| S-EPMC9379904 | biostudies-literature

Two distinct catalytic pathways for GH43 xylanolytic enzymes unveiled by X-ray and QM/MM simulations.

Project description:Xylanolytic enzymes from glycoside hydrolase family 43 (GH43) are involved in the breakdown of hemicellulose, the second most abundant carbohydrate in plants. Here, we kinetically and mechanistically describe the non-reducing-end xylose-releasing exo-oligoxylanase activity and report the crystal structure of a native GH43 Michaelis complex with its substrate prior to hydrolysis. Two distinct calcium-stabilized conformations of the active site xylosyl unit are found, suggesting two alternative catalytic routes. These results are confirmed by QM/MM simulations that unveil the complete hydrolysis mechanism and identify two possible reaction pathways, involving different transition state conformations for the cleavage of xylooligosaccharides. Such catalytic conformational promiscuity in glycosidases is related to the open architecture of the active site and thus might be extended to other exo-acting enzymes. These findings expand the current general model of catalytic mechanism of glycosidases, a main reaction in nature, and impact on our understanding about their interaction with substrates and inhibitors.

| S-EPMC7809346 | biostudies-literature

Mapping protein electron transfer pathways with QM/MM methods.

Project description:Mixed quantum mechanics/molecular mechanics (QM/MM) methods offer a valuable computational tool for understanding the electron transfer pathway in protein-substrate interactions and protein-protein complexes. These hybrid methods are capable of solving the Schrödinger equation on a small subset of the protein, the quantum region, describing its electronic structure under the polarization effects of the remainder of the protein. By selectively turning on and off different residues in the quantum region, we are able to obtain the electron pathway for short- and large-range interactions. Here, we summarize recent studies involving the protein-substrate interaction in cytochrome P450 camphor, ascorbate peroxidase and cytochrome c peroxidase, and propose a novel approach for the long-range protein-protein electron transfer. The results on ascorbate peroxidase and cytochrome c peroxidase reveal the importance of the propionate groups in the electron transfer pathway. The long-range protein-protein electron transfer has been studied on the cytochrome c peroxidase-cytochrome c complex. The results indicate the importance of Phe82 and Cys81 on cytochrome c, and of Asn196, Ala194, Ala176 and His175 on cytochrome c peroxidase.

| S-EPMC2706105 | biostudies-literature

Exploring Covalent Docking Mechanisms of Boron-Based Inhibitors to Class A, C and D β-Lactamases Using Time-dependent Hybrid QM/MM Simulations.

Project description:Recently, molecular covalent docking has been extensively developed to design new classes of inhibitors that form chemical bonds with their biological targets. This strategy for the design of such inhibitors, in particular boron-based inhibitors, holds great promise for the vast family of β-lactamases produced, inter alia, by Gram-negative antibiotic-resistant bacteria. However, the description of covalent docking processes requires a quantum-mechanical approach, and so far, only a few studies of this type have been presented. This study accurately describes the covalent docking process between two model inhibitors - representing two large families of inhibitors based on boronic-acid and bicyclic boronate scaffolds, and three β-lactamases which belong to the A, C, and D classes. Molecular fragments containing boron can be converted from a neutral, trigonal, planar state with sp2 hybridization to the anionic, tetrahedral sp3 state in a process sometimes referred to as morphing. This study applies multi-scale modeling methods, in particular, the hybrid QM/MM approach which has predictive power reaching well beyond conventional molecular modeling. Time-dependent QM/MM simulations indicated several structural changes and geometric preferences, ultimately leading to covalent docking processes. With current computing technologies, this approach is not computationally expensive, can be used in standard molecular modeling and molecular design works, and can effectively support experimental research which should allow for a detailed understanding of complex processes important to molecular medicine. In particular, it can support the rational design of covalent boron-based inhibitors for β-lactamases as well as for many other enzyme systems of clinical relevance, including SARS-CoV-2 proteins.

| S-EPMC8380965 | biostudies-literature

Mechanism of Ampicillin Hydrolysis by New Delhi Metallo-β-Lactamase 1: Insight From QM/MM MP2 Calculation.

Project description:The New Delhi metallo-β-lactamase 1 (NDM-1) can hydrolyze nearly all clinically important β-lactam antibiotics, narrowing the options for effective treatment of bacterial infections. QM/MM MP2 calculations are performed to reveal the mechanism of ampicillin hydrolysis catalyzed by NDM-1. It is found that the rate-determining step is the dissociation of hydrolyzed ampicillin from the NDM-1 active site, which requires a proton transfer from the bridging neutral water molecule to the newly formed carboxylate group. The precedent reaction steps, including the hydroxide nucleophilic addition, CN bond cleavage, and the protonation of the negative lactam N atom by a solvent water molecule, all require insignificant activation free energies. The calculated activation free energy for this rate-determining proton transfer step is 16.0 kcal/mol, in good agreement with experimental values of 13.7 ~ 14.7 kcal/mol. This proton transfer step exhibits a solvent hydrogen-deuterium kinetic isotope effect of 3.4, consistent with several experimental kinetic results.

| S-EPMC11619567 | biostudies-literature

QM/MM Modeling of the Flavin Functionalization in the RutA Monooxygenase.

Project description:Oxygenase activity of the flavin-dependent enzyme RutA is commonly associated with the formation of flavin-oxygen adducts in the enzyme active site. We report the results of quantum mechanics/molecular mechanics (QM/MM) modeling of possible reaction pathways initiated by various triplet state complexes of the molecular oxygen with the reduced flavin mononucleotide (FMN) formed in the protein cavities. According to the calculation results, these triplet-state flavin-oxygen complexes can be located at both re-side and si-side of the isoalloxazine ring of flavin. In both cases, the dioxygen moiety is activated by electron transfer from FMN, stimulating the attack of the arising reactive oxygen species at the C4a, N5, C6, and C8 positions in the isoalloxazine ring after the switch to the singlet state potential energy surface. The reaction pathways lead to the C(4a)-peroxide, N(5)-oxide, or C(6)-hydroperoxide covalent adducts or directly to the oxidized flavin, depending on the initial position of the oxygen molecule in the protein cavities.

| S-EPMC10005588 | biostudies-literature

Predictive QM/MM Modeling of Modulations in Protein-Protein Binding by Lysine Methylation.

Project description:Lysine methylation is a key regulator of protein-protein binding. The amine group of lysine can accept up to three methyl groups, and experiments show that protein-protein binding free energies are sensitive to the extent of methylation. These sensitivities have been rationalized in terms of chemical and structural features present in the binding pockets of methyllysine binding domains. However, understanding their specific roles requires an energetic analysis. Here we propose a theoretical framework to combine quantum and molecular mechanics methods, and compute the effect of methylation on protein-protein binding free energies. The advantages of this approach are that it derives contributions from all local non-trivial effects of methylation on induction, polarizability and dispersion directly from self-consistent electron densities, and at the same time determines contributions from well-characterized hydration effects using a computationally efficient classical mean field method. Limitations of the approach are discussed, and we note that predicted free energies of fourteen out of the sixteen cases agree with experiment. Critical assessment of these cases leads to the following overarching principles that drive methylation-state recognition by protein domains. Methylation typically reduces the pairwise interaction between proteins. This biases binding toward lower methylated states. Simultaneously, however, methylation also makes it easier to partially dehydrate proteins and place them in protein-protein complexes. This latter effect biases binding in favor of higher methylated states. The overall effect of methylation on protein-protein binding depends ultimately on the balance between these two effects, which is observed to be tuned via several combinations of local features.

| S-EPMC9801414 | biostudies-literature

QM/MM calculations with deMon2k.

Project description:The density functional code deMon2k employs a fitted density throughout (Auxiliary Density Functional Theory), which offers a great speed advantage without sacrificing necessary accuracy. Powerful Quantum Mechanical/Molecular Mechanical (QM/MM) approaches are reviewed. Following an overview of the basic features of deMon2k that make it efficient while retaining accuracy, three QM/MM implementations are compared and contrasted. In the first, deMon2k is interfaced with the CHARMM MM code (CHARMM-deMon2k); in the second MM is coded directly within the deMon2k software; and in the third the Chemistry in Ruby (Cuby) wrapper is used to drive the calculations. Cuby is also used in the context of constrained-DFT/MM calculations. Each of these implementations is described briefly; pros and cons are discussed and a few recent applications are described briefly. Applications include solvated ions and biomolecules, polyglutamine peptides important in polyQ neurodegenerative diseases, copper monooxygenases and ultra-rapid electron transfer in cryptochromes.

| S-EPMC6272552 | biostudies-literature

A Multidimensional B-Spline Correction for Accurate Modeling Sugar Puckering in QM/MM Simulations.

Project description:The computational efficiency of approximate quantum mechanical methods allows their use for the construction of multidimensional reaction free energy profiles. It has recently been demonstrated that quantum models based on the neglect of diatomic differential overlap (NNDO) approximation have difficulty modeling deoxyribose and ribose sugar ring puckers and thus limit their predictive value in the study of RNA and DNA systems. A method has been introduced in our previous work to improve the description of the sugar puckering conformational landscape that uses a multidimensional B-spline correction map (BMAP correction) for systems involving intrinsically coupled torsion angles. This method greatly improved the adiabatic potential energy surface profiles of DNA and RNA sugar rings relative to high-level ab initio methods even for highly problematic NDDO-based models. In the present work, a BMAP correction is developed, implemented, and tested in molecular dynamics simulations using the AM1/d-PhoT semiempirical Hamiltonian for biological phosphoryl transfer reactions. Results are presented for gas-phase adiabatic potential energy surfaces of RNA transesterification model reactions and condensed-phase QM/MM free energy surfaces for nonenzymatic and RNase A-catalyzed transesterification reactions. The results show that the BMAP correction is stable, efficient, and leads to improvement in both the potential energy and free energy profiles for the reactions studied, as compared with ab initio and experimental reference data. Exploration of the effect of the size of the quantum mechanical region indicates the best agreement with experimental reaction barriers occurs when the full CpA dinucleotide substrate is treated quantum mechanically with the sugar pucker correction.

| S-EPMC5839098 | biostudies-literature

The QM/MM molecular dynamics and free energy simulations of the acylation reaction catalyzed by the serine-carboxyl peptidase kumamolisin-As.

Project description:Quantum mechanical/molecular mechanical molecular dynamics and free energy simulations are performed to study the acylation reaction catalyzed by kumamolisin-As, a serine-carboxyl peptidase, and to elucidate the catalytic mechanism and the origin of substrate specificity. It is demonstrated that the nucleophilic attack by the serine residue on the substrate may not be the rate-limiting step for the acylation of the GPH*FF substrate. The present study also confirms the earlier suggestions that Asp164 acts as a general acid during the catalysis and that the electrostatic oxyanion hole interactions may not be sufficient to lead a stable tetrahedral intermediate along the reaction pathway. Moreover, Asp164 is found to act as a general base during the formation of the acyl-enzyme from the tetrahedral intermediate. The role of dynamic substrate assisted catalysis (DSAC) involving His at the P1 site of the substrate is examined for the acylation reaction. It is demonstrated that the bond-breaking and -making events at each stage of the reaction trigger a change of the position for the His side chain and lead to the formation of the alternative hydrogen bonds. The back and forth movements of the His side chain between the C=O group of Pro at P2 and Odelta2 of Asp164 in a ping-pong-like mechanism and the formation of the alternative hydrogen bonds effectively lower the free energy barriers for both the nucleophilic attack and the acyl-enzyme formation and may therefore contribute to the relatively high activity of kumamolisin-As toward the substrates with His at the P1 site.

| S-EPMC2533263 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data