English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Pro

Presents the zaia usage as premium feature

ZAIA

Presents AI Discovery search usage as a premium feature

AI Discovery

Presents AI Discovery explain and summary usage as a premium feature

Content Analysis

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Presents the pdf analysis as premium feature

PDF Analysis

1500 Top-up

3000 Top-up

Zendy Basic

2500 Top-up

Zendy Unlimited

Presents the access of premium content as premium feature

Premium Content

Nitroalkane oxidase (NAO) from Fusarium oxysporum catalyzes the oxidation of neutral nitroalkanes to the corresponding aldehydes or ketones with the production of H(2)O(2) and nitrite. The flavoenzyme is a new member of the acyl-CoA dehydrogenase (ACAD) family, but it does not react with acyl-CoA substrates. We present the 2.2 A resolution crystal structure of NAO trapped during the turnover of nitroethane as a covalent N5-FAD adduct (ES*). The homotetrameric structure of ES* was solved by MAD phasing with 52 Se-Met sites in an orthorhombic space group. The electron density for the N5-(2-nitrobutyl)-1,5-dihydro-FAD covalent intermediate is clearly resolved. The structure of ES was used to solve the crystal structure of oxidized NAO at 2.07 A resolution. The c axis for the trigonal space group of oxidized NAO is 485 A, and there are six subunits (1(1)/(2) holoenzymes) in the asymmetric unit. Four of the active sites contain spermine (EI), a weak competitive inhibitor, and two do not contain spermine (E(ox)). The active-site structures of E(ox), EI, and ES* reveal a hydrophobic channel that extends from the exterior of the protein and terminates at Asp402 and the N5 position on the re face of the FAD. Thus, Asp402 is in the correct position to serve as the active-site base, where it is proposed to abstract the alpha proton from neutral nitroalkane substrates. The structures for NAO and various members of the ACAD family overlay with root-mean-square deviations between 1.7 and 3.1 A. The homologous region typically spans more than 325 residues and includes Glu376, which is the active-site base in the prototypical member of the ACAD family. However, NAO and the ACADs exhibit differences in hydrogen-bonding patterns between the respective active-site base, substrate molecules, and FAD. These likely differentiate NAO from the homologues and, consequently, are proposed to result in the unique reaction mechanism of NAO.

Crystal Structures of Nitroalkane Oxidase: Insights into the Reaction Mechanism from a Covalent Complex of the Flavoenzyme Trapped during Turnover