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Investigates the possible intermediates in the mechanism of dihydrogen activation by the nickel-iron center of nickel-iron hydrogenases using quantum chemical methods. Structural and electronic properties of the active site models; Spectroscopical identification of the enzymes; Redox chemistry of the hydrogenases; Role of the cysteine ligands in the reactions.

Objectives: The lipase gene lipSR1 isolated from oil-contaminated soil exhibits high hydrolytic activity for short-chain fatty acid substrates. A single calcium ion is required to anchor the lid of LipSR1 in an open conformation by coordination with two aspartate residues and three other residues in the lid. The lid of LipSR1 is anchored by Ca2+, which is coordinated by side-chain carboxyl oxygens of Asp153 and Asp157, carbonyl oxygens of Thr118 and Ser144, and the side chain of Gln120. Results: D157A, D153R, Q120A, S144A, and T118A mutants were produced by site-directed mutagenesis in this study. Analyses of hydrolytic activity and thermostability showed that the properties of D157A, D153R, Q120A, and S144A were almost lost, suggesting that Asp157, Asp153, Gln120, and Ser144 are important residues for LipSR1. However, the catalytic performance of T118A was clearly maintained. Moreover, the thermostability of mutant T118A was higher than that of wild-type LipSR1. Conclusions: These results indicated that mutation of threonine at position 118 improved the stability of the enzyme at high temperature. [ABSTRACT FROM AUTHOR]

Several Pseudomonas sp. CR611 Lip I.3 mutants with overall increased activity and a shift towards longer chain substrates were constructed. Substitution of residues Y29 and W310 by smaller amino acids provided increased activity on C18-substrates. Residues G152 and S154, modified to study their influence on interfacial activation, displayed a five and eleven fold increased activity. [ABSTRACT FROM AUTHOR]

The protein product of gene At1g53580 from Arabidopsis thaliana possesses 54% sequence identity to a human enzyme that has been implicated in the rare disorder ethylmalonic encephalopathy. The structure of the At1g53580 protein has been solved to a nominal resolution of 1.48 Å. This structure reveals tertiary structure differences between the ETHE1-like enzyme and glyoxalase II enzymes that are likely to account for differences in reaction chemistry and multimeric state between the two types of enzymes. In addition, the Arabidopsis ETHE1 protein is used as a model to explain the significance of several mutations in the human enzyme that have been observed in patients with ethylmalonic encephalopathy. [ABSTRACT FROM AUTHOR]

Learning from nature is a strategy for catalyst development. Its philosophy is that creative designs of high performance catalysts can be obtained from advanced understanding of catalysts selected by nature after billions of years of evolution, such as enzyme. A typical demonstration of such strategy is the developing of catalysts for large‐scale hydrogen production. Hydrogenases due to their impressive performance in catalyzing hydrogen oxidation/production, have been selected as a prototype for human being's learning to achieve better design. Fully understand the structures of hydrogenases and their catalysis mechanisms are essential to reproduce and even outperform this prototype. This article reviews the computational efforts in recent years, focusing on density functional theory calculations on [NiFe] hydrogenases. It summarizes the current knowledge regarding the identification of active sites in [NiFe] hydrogenases and reaction cycles of hydrogen oxidation, followed with a brief collection and discussion of bio‐inspired molecular catalysts derived from [NiFe] hydrogenase model. The capacity of computational calculations for the clarification of catalyst geometries and reaction mechanisms has been highlighted. This article is categorized under:Structure and Mechanism > Computational Biochemistry and BiophysicsStructure and Mechanism > Computational Materials ScienceStructure and Mechanism > Reaction Mechanisms and Catalysis [ABSTRACT FROM AUTHOR]