Ornithine cyclodeaminase (OCD) is an NAD+-dependent deaminase that is found in bacterial species such as Pseudomonas putida. Importantly, it catalyzes the direct conversion of the amino acid L-ornithine to L-proline. Using molecular dynamics (MD) and a hybrid quantum mechanics/molecular mechanics (QM/MM) method in the ONIOM formalism, the catalytic mechanism of OCD has been examined. The rate limiting step is calculated to be the initial step in the overall mechanism: hydride transfer from the L-ornithine's C(α)-H group to the NAD+ cofactor with concomitant formation of a C(α)=NH(2)+ Schiff base with a barrier of 90.6 kJ mol-1. Importantly, no water is observed within the active site during the MD simulations suitably positioned to hydrolyze the C(α)=NH(2)+ intermediate to form the corresponding carbonyl. Instead, the reaction proceeds via a non-hydrolytic mechanism involving direct nucleophilic attack of the δ-amine at the C(α)-position. This is then followed by cleavage and loss of the α-NH(2) group to give the Δ1-pyrroline-2-carboxylate that is subsequently reduced to L-proline.
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http://dx.doi.org/10.3390/ijms131012994 | DOI Listing |
J Biomol Struct Dyn
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University of Health Sciences, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam.
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January 2025
College of Applied Medical Sciences, lmam Abdulrahman Bin Faisal University (lAU), Dammam, Saudi Arabia.
The present study explores the conformational dynamics of the membrane protein of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) within the Endoplasmic Reticulum-Golgi Intermediate Compartment (ERGIC) complex using an all-atomistic molecular dynamics simulation approach. Significant structural changes were observed in the N-terminal, C-terminal, transmembrane, and beta-sheet sandwich domains of the MERS-CoV membrane protein. This study also highlights the structural similarities between the MERS-CoV and the SARS-CoV-2 membrane proteins, particularly in how both exhibit a distinct kink in the transmembrane helix caused by aromatic residue-lipid interactions.
View Article and Find Full Text PDFSci Rep
January 2025
College of Mechanical Engineering, Zhejiang University of Technology, No.18, Chaowang Road, Hangzhou, 310014, Zhejiang Province, China.
To observe the chemical mechanical polishing (CMP) process at the atomic scale, reactive force field molecular dynamics (ReaxFF-MD) was employed to simulate the polishing of 6 H-SiC under three conditions: dry, pure water, and HO solution. This study examined the reactants on the surface of 6 H-SiC during the reaction in the HO solution, along with the dissociation and adsorption processes of HO and water molecules. The mechanisms for atom removal during the CMP process were elucidated.
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January 2025
School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Vibrio vulnificus is a significant zoonotic pathogen that causes severe vibriosis in humans and fish. The lack of a national annual surveillance program in China has hindered understanding of its epidemiological characteristics and genetic diversity. This study characterized 150 V.
View Article and Find Full Text PDFSci Rep
January 2025
Bioinformatics Centre, Savitribai Phule Pune University, Pune, Maharashtra, 411007, India.
COVID-19 has proved to be a global health crisis during the pandemic, and the emerging JN.1 variant is a potential threat. Therefore, finding alternative antivirals is of utmost priority.
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