A Catalytic Mechanism for Cysteine N-Terminal Nucleophile Hydrolases, as Revealed by Free Energy Simulations

The N-terminal nucleophile (Ntn) hydrolases are a superfamily of enzymes specialized in the hydrolytic cleavage of amide bonds. Even though several members of this family are emerging as innovative drug targets for cancer, inflammation, and pain, the processes through which they catalyze amide hydrolysis remains poorly understood. In particular, the catalytic reactions of cysteine Ntn-hydrolases have never been investigated from a mechanistic point of view. In the present study, we used free energy simulations in the quantum mechanics/molecular mechanics framework to determine the reaction mechanism of amide hydrolysis catalyzed by the prototypical cysteine Ntn-hydrolase, conjugated bile acid hydrolase (CBAH). The computational analyses, which were confirmed in water and using different CBAH mutants, revealed the existence of a chair-like transition state, which might be one of the specific features of the catalytic cycle of Ntn-hydrolases. Our results offer new insights on Ntn-mediated hydrolysis and suggest possible strategies for the creation of therapeutically useful inhibitors

Ассоциации между I/D полиморфизмом ACE гена и развитием асфиксии у новорожденных

Abstract: This article studies the influence of ACE gene I/D polymorphism on the asphyxia development in the term infants. It is shown that children with II genotype of ACE gene are less odds ratio to develop birth asphyxia, and her severe. Heart rate, blood pressure, urine output hourly, as well as the rate of dopamine use in children with different genotypes of ACE gene is not different; Аннотация: Статья посвящена изучению влияния I/D полиморфизма ACE гена на развитие асфиксии у доношенных новорожденных. Показано, что дети с II генотипом АСЕ гена имеют меньше шансов в развитии асфиксии и ее тяжелого течения. Частота сердечных сокращений, артериальное давление, почасовый диурез, а также частота применения дофамину у детей с разными генотипами АСЕ гена не отличались

Improved annotation of conjugated bile acid hydrolase superfamily members in Gram-positive bacteria.

Item does not contain fulltextMost Gram-positive bacteria inhabiting the gastrointestinal tract are capable of hydrolysing bile salts. Bile salt hydrolysis is thought to play an important role in various biological processes in the host. Therefore, correct annotation of bacterial bile salt hydrolases (Bsh) in public databases (EC 3.5.1.24) is of importance, especially for lactobacilli, which are considered to play a major role in bile salt hydrolysis in vivo. In the present study, all enzymes listed in public databases that belong to the Bsh family and the closely related penicillin V acylase (Pva; EC 3.5.1.11) family were compared with the sequences annotated as Bsh in Lactobacillus plantarum WCFS1, as an example. In Gram-positive bacteria, a clear distinction was made between the two families using sequence alignment, phylogenetic clustering, and protein homology modelling. Biochemical and structural data on experimentally verified Bsh and Pva enzymes were used for validation of function prediction. Hidden Markov models were constructed from the sequence alignments to enable a more accurate prediction of Bsh-encoding genes, and their distinction from those encoding members of the Pva family. Many Pva-related sequences appeared to be annotated incorrectly as Bsh in public databases. This refinement in the annotation of Bsh family members influences the prediction of the function of bsh-like genes in species of the genus Lactobacillus, and it is discussed in detail