Copper nitrite reductase from Sinorhizobium meliloti 2011: Crystal structure and interaction with the physiological versus a nonmetabolically related cupredoxin-like mediator.

We report the crystal structure of the copper-containing nitrite reductase (NirK) from the Gram-negative bacterium Sinorhizobium meliloti 2011 (Sm), together with complex structural alignment and docking studies with both non-cognate and the physiologically related pseudoazurins, SmPaz1 and SmPaz2, respectively. S. meliloti is a rhizobacterium used for the formulation of Medicago sativa bionoculants, and SmNirK plays a key role in this symbiosis through the denitrification pathway.

Alternative Splicing of the Aflatoxin-Associated Baeyer⁻Villiger Monooxygenase from : Characterisation of MoxY Isoforms.

Aflatoxins are carcinogenic mycotoxins that are produced by the filamentous fungus , a contaminant of numerous food crops. Aflatoxins are synthesised via the aflatoxin biosynthesis pathway, with the enzymes involved encoded by the aflatoxin biosynthesis gene cluster. MoxY is a type I Baeyer⁻Villiger monooxygenase (BVMO), responsible for the conversion of hydroxyversicolorone (HVN) and versicolorone (VN) to versiconal hemiacetal acetate (VHA) and versiconol acetate (VOAc), respectively.

Native roles of Baeyer-Villiger monooxygenases in the microbial metabolism of natural compounds.

Covering: up to end of June 2018 Baeyer-Villiger monooxygenases (BVMOs) are flavin-dependent enzymes that catalyse the oxidation of ketones and cyclic ketones to esters and lactones, respectively, by using molecular oxygen and NAD(P)H. BVMOs also catalyse sulfoxidations and N-oxidations. BVMOs are widely studied as attractive biocatalysts, but also catalyse key reactions in metabolic pathways of the organisms from which they are sourced.

Alkyl Formate Ester Synthesis by a Fungal Baeyer-Villiger Monooxygenase.

We investigated Baeyer-Villiger monooxygenase (BVMO)-mediated synthesis of alkyl formate esters, which are important flavor and fragrance products. A recombinant fungal BVMO from Aspergillus flavus was found to transform a selection of aliphatic aldehydes into alkyl formates with high regioselectivity. Near complete conversion of 10 mm octanal was achieved within 8 h with a regiomeric excess of ∼80 %.

Structural and Catalytic Characterization of a Fungal Baeyer-Villiger Monooxygenase.

Baeyer-Villiger monooxygenases (BVMOs) are biocatalysts that convert ketones to esters. Due to their high regio-, stereo- and enantioselectivity and ability to catalyse these reactions under mild conditions, they have gained interest as alternatives to chemical Baeyer-Villiger catalysts. Despite their widespread occurrence within the fungal kingdom, most of the currently characterized BVMOs are from bacterial origin.