Structure-based clustering and mutagenesis of bacterial tannases reveals the importance and diversity of active site-capping domains.

Tannins are critical plant defense metabolites, enriched in bark and leaves, that protect against microorganisms and insects by binding to and precipitating proteins. Hydrolyzable tannins contain ester bonds which can be cleaved by tannases-serine hydrolases containing so-called "cap" domains covering their active sites. However, comprehensive insights into the biochemical properties and structural diversity of tannases are limited, especially regarding their cap domains.

Enabling Aromatic Hydroxylation in a Cytochrome P450 Monooxygenase Enzyme through Protein Engineering.

The cytochrome P450 (CYP) family of heme monooxygenases catalyse the selective oxidation of C-H bonds under ambient conditions. The CYP199A4 enzyme from Rhodopseudomonas palustris catalyses aliphatic oxidation of 4-cyclohexylbenzoic acid but not the aromatic oxidation of 4-phenylbenzoic acid, due to the distinct mechanisms of aliphatic and aromatic oxidation. The aromatic substrates 4-benzyl-, 4-phenoxy- and 4-benzoyl-benzoic acid and methoxy-substituted phenylbenzoic acids were assessed to see if they could achieve an orientation more amenable to aromatic oxidation.

Why do silanes reduce electron-rich phosphine oxides faster than electron-poor phosphine oxides?

Organophosphine-mediated reactions that generate P[double bond, length as m-dash]O-bonded byproducts can be transformed into catalytic processes by reducing the R3P[double bond, length as m-dash]O byproduct back to PR3in situ with a silane. DFT calculations explain why the most readily reduced phosphine oxides are those incorporating electron-rich (e.g.