QM/MM Molecular Dynamics Investigations of the Substrate Binding of Leucotriene A4 Hydrolase: Implication for the Catalytic Mechanism

2018 ◽  
Vol 122 (29) ◽  
pp. 7253-7263 ◽  
Author(s):  
Xia Mu ◽  
Dingguo Xu
Keyword(s):  
Molecular Dynamics ◽  
Catalytic Mechanism ◽  
Substrate Binding

Copper–oxygen Dynamics in Tyrosinase

2019 ◽  
Author(s):  
Nobutaka Fujieda ◽  
Sachiko Yanagisawa ◽  
Minoru Kubo ◽  
Genji Kurisu ◽  
Shinobu Itoh
Keyword(s):  
Catalytic Mechanism ◽  
Substrate Binding ◽  
Active Form ◽  
Copper Ion ◽  
Atomic Resolution ◽  
Oxygen Species ◽  
X Ray ◽  
Oxygen Dynamics ◽  
Insight Into ◽  
Copper Centre

To unveil the activation of dioxygen on the copper centre (Cu<sub>2</sub>O<sub>2</sub>core) of tyrosinase, we performed X-ray crystallograpy with active-form tyrosinase at near atomic resolution. This study provided a novel insight into the catalytic mechanism of the tyrosinase, including the rearrangement of copper-oxygen species as well as the intramolecular migration of copper ion induced by substrate-binding.<br>

Unraveling cGAS catalytic mechanism upon DNA activation through molecular dynamics simulations

2021 ◽  
Author(s):  
Jordi Soler ◽  
Pedro Paiva ◽  
Maria Joao Joao Ramos ◽  
Pedro Alexandrino Fernandes ◽  
Marie Brut
Keyword(s):  
Molecular Dynamics ◽  
Dna Binding ◽  
Molecular Dynamics Simulations ◽  
Cyclic Gmp ◽  
Catalytic Mechanism ◽  
System P ◽  
Dynamics Simulations ◽  
Cyclic Dinucleotide

Cyclic GMP-AMP Synthase (cGAS) is activated upon DNA binding and catalyzes the synthesis of 2’,3’-cGAMP from GTP and ATP. This cyclic dinucleotide is a messenger that triggers the autoimmune system...

Structure and mechanism of the γ-glutamyl-γ-aminobutyrate hydrolase SpuA from Pseudomonas aeruginosa

2021 ◽  
Vol 77 (10) ◽  
pp. 1305-1316
Author(s):  
Yujing Chen ◽  
Haizhu Jia ◽  
Jianyu Zhang ◽  
Yakun Liang ◽  
Ruihua Liu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Catalytic Mechanism ◽  
Substrate Binding ◽  
Binding Pocket ◽  
Class I ◽  
Polyamine Metabolism ◽  
Binding Assays ◽  
Starting Point ◽  
Family Activity ◽  
Living Organisms

Polyamines are important regulators in all living organisms and are implicated in essential biological processes including cell growth, differentiation and apoptosis. Pseudomonas aeruginosa possesses an spuABCDEFGHI gene cluster that is involved in the metabolism and uptake of two polyamines: spermidine and putrescine. In the proposed γ-glutamylation–putrescine metabolism pathway, SpuA hydrolyzes γ-glutamyl-γ-aminobutyrate (γ-Glu-GABA) to glutamate and γ-aminobutyric acid (GABA). In this study, crystal structures of P. aeruginosa SpuA are reported, confirming it to be a member of the class I glutamine amidotransferase (GAT) family. Activity and substrate-binding assays confirm that SpuA exhibits a preference for γ-Glu-GABA as a substrate. Structures of an inactive H221N mutant were determined with bound glutamate thioester intermediate or glutamate product, thus delineating the active site and substrate-binding pocket and elucidating the catalytic mechanism. The crystal structure of another bacterial member of the class I GAT family from Mycolicibacterium smegmatis (MsGATase) in complex with glutamine was determined for comparison and reveals a binding site for glutamine. Activity assays confirm that MsGATase has activity for glutamine as a substrate but not for γ-Glu-GABA. The work reported here provides a starting point for further investigation of polyamine metabolism in P. aeruginosa.

scholarly journals A crystallographic study of the Toho-1 β-lactamase acylation mechanism

2014 ◽  
Vol 70 (a1) ◽  
pp. C1207-C1207
Author(s):  
Leighton Coates
Keyword(s):  
Hydrogen Bonding ◽  
Transition State ◽  
Active Site ◽  
Catalytic Mechanism ◽  
Substrate Binding ◽  
Ligand Complex ◽  
Transition State Analog ◽  
Hydrogen Bonding Interactions ◽  
Active Site Region ◽  
Neutron Crystallography

β-lactam antibiotics have been used effectively over several decades against many types of highly virulent bacteria. The predominant cause of resistance to these antibiotics in Gram-negative bacterial pathogens is the production of serine β-lactamase enzymes. A key aspect of the class A serine β-lactamase mechanism that remains unresolved and controversial is the identity of the residue acting as the catalytic base during the acylation reaction. Multiple mechanisms have been proposed for the formation of the acyl-enzyme intermediate that are predicated on understanding the protonation states and hydrogen-bonding interactions among the important residues involved in substrate binding and catalysis of these enzymes. For resolving a controversy of this nature surrounding the catalytic mechanism, neutron crystallography is a powerful complement to X-ray crystallography that can explicitly determine the location of deuterium atoms in proteins, thereby directly revealing the hydrogen-bonding interactions of important amino acid residues. Neutron crystallography was used to unambiguously reveal the ground-state active site protonation states and the resulting hydrogen-bonding network in two ligand-free Toho-1 β-lactamase mutants which provided remarkably clear pictures of the active site region prior to substrate binding and subsequent acylation [1,2] and an acylation transition-state analog, benzothiophene-2-boronic acid (BZB), which was also isotopically enriched with 11B. The neutron structure revealed the locations of all deuterium atoms in the active site region and clearly indicated that Glu166 is protonated in the BZB transition-state analog complex. As a result, the complete hydrogen-bonding pathway throughout the active site region could then deduced for this protein-ligand complex that mimics the acylation tetrahedral intermediate [3].

scholarly journals Structures of an engineered phospholipase D with specificity for secondary alcohol transphosphatidylation: Insights into plasticity of substrate binding and activation

2021 ◽  
Author(s):  
Ariela Samantha ◽  
Jasmina Damnjanović ◽  
Yugo Iwasaki ◽  
Hideo Nakano ◽  
Alice Vrielink
Keyword(s):  
Phospholipase D ◽  
Catalytic Mechanism ◽  
Inositol Phosphate ◽  
Substrate Binding ◽  
Secondary Alcohol ◽  
Molecular Size ◽  
Underlying Mechanism ◽  
Head Group ◽  
Wild Type ◽  
Primary Alcohols

Phospholipase D (PLD) is an enzyme useful for the enzymatic modification of phospholipids.  In the presence of primary alcohols, the enzyme catalyses transphosphatidylation of the head group of phospholipid substrates to synthesize a modified phospholipid product.  However, the enzyme is specific for primary alcohols and thus the limitation of the molecular size of the acceptor compounds has restricted the type of phospholipid species that can be synthesised.  An engineered variant of PLD from Streptomycesantibioticus termed TNYR SaPLD was developed capable of synthesizing 1-phosphatidylinositol with positional specificity of up to 98%. To gain a better understanding of the substrate binding features of the TNYR SaPLD, crystal structures have been determined for the free enzyme and its complexes with phosphate, phosphatidic acid and 1-inositol phosphate.  Comparisons of these structures with the wild-type SaPLD show a larger binding site able to accommodate a bulkier secondary alcohol substrate as well as changes to the position of a flexible surface loop proposed to be involved in substrate recognition.  The complex of the active TNYR SaPLD with 1-inositol phosphate reveals a covalent intermediate adduct with the ligand bound to H442 rather than to H168, the proposed nucleophile in the wild type enzyme.  This structural feature suggests that the enzyme exhibits plasticity of the catalytic mechanism different from what has been reported to date for PLDs.  These structural studies provide insights into the underlying mechanism that governs the recognition of myo-inositol by TNYR SaPLD, and an important foundation for further studies of the catalytic mechanism.

A molecular dynamics study of the complete binding process of meropenem to New Delhi metallo-β-lactamase 1

2018 ◽  
Vol 20 (9) ◽  
pp. 6409-6420 ◽  
Author(s):  
Juan Duan ◽  
Chuncai Hu ◽  
Jiafan Guo ◽  
Lianxian Guo ◽  
Jia Sun ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Substrate Binding ◽  
New Delhi ◽  
Binding Process ◽  
Dynamics Simulations

We have investigated the substrate-binding pathways of NDM-1 via unbiased molecular dynamics simulations and metadynamics.

scholarly journals Molecular dynamics and structure function analysis show that substrate binding and specificity are major forces in the functional diversification of Eqolisins

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Nicolás Stocchi ◽  
María Victoria Revuelta ◽  
Priscila Ailín Lanza Castronuovo ◽  
D. Mariano A. Vera ◽  
Arjen ten Have
Keyword(s):  
Molecular Dynamics ◽  
Structure Function ◽  
Function Analysis ◽  
Substrate Binding ◽  
Functional Diversification
Sign in / Sign up

Export Citation Format

Share Document