4CNK

L-Aminoacetone oxidase from Streptococcus oligofermentans belongs to a new 3-domain family of bacterial flavoproteins

Summary for 4CNK

• Entry DOI: 10.2210/pdb4cnk/pdb
• Related: 4CNJ
• Descriptor: L-AMINO ACID OXIDASE, FLAVIN-ADENINE DINUCLEOTIDE, O-METHYL-GLYCINE, ... (6 entities in total)
• Functional Keywords: oxidoreductase, flavoproteins
• Biological source: STREPTOCOCCUS OLIGOFERMENTANS
• Total number of polymer chains: 2
• Total formula weight: 89101.45

Authors

Molla, G.,Nardini, M.,Motta, P.,D'Arrigo, P.,Bolognesi, M.,Pollegioni, L. (deposition date: 2014-01-23, release date: 2014-10-15, Last modification date: 2023-12-20)

Primary citation

Molla, G.,Nardini, M.,Motta, P.,D'Arrigo, P.,Panzeri, W.,Pollegioni, L.
Aminoacetone Oxidase from Streptococcus Oligofermentas Belongs to a New Three-Domain Family of Bacterial Flavoproteins.
Biochem.J., 464:387-, 2014

PubMed Abstract: The aaoSo gene from Streptococcus oligofermentans encodes a 43 kDa flavoprotein, aminoacetone oxidase (SoAAO), which was reported to possess a low catalytic activity against several different L-amino acids; accordingly, it was classified as an L-amino acid oxidase. Subsequently, SoAAO was demonstrated to oxidize aminoacetone (a pro-oxidant metabolite), with an activity ~25-fold higher than the activity displayed on L-lysine, thus lending support to the assumption of aminoacetone as the preferred substrate. In the present study, we have characterized the SoAAO structure-function relationship. SoAAO is an FAD-containing enzyme that does not possess the classical properties of the oxidase/dehydrogenase class of flavoproteins (i.e. no flavin semiquinone formation is observed during anaerobic photoreduction as well as no reaction with sulfite) and does not show a true L-amino acid oxidase activity. From a structural point of view, SoAAO belongs to a novel protein family composed of three domains: an α/β domain corresponding to the FAD-binding domain, a β-domain partially modulating accessibility to the coenzyme, and an additional α-domain. Analysis of the reaction products of SoAAO on aminoacetone showed 2,5-dimethylpyrazine as the main product; we propose that condensation of two aminoacetone molecules yields 3,6-dimethyl-2,5-dihydropyrazine that is subsequently oxidized to 2,5-dimethylpyrazine. The ability of SoAAO to bind two molecules of the substrate analogue O-methylglycine ligand is thought to facilitate the condensation reaction. A specialized role for SoAAO in the microbial defence mechanism related to aminoacetone catabolism through a pathway yielding dimethylpyrazine derivatives instead of methylglyoxal can be proposed.

PubMed: 25269103
DOI: 10.1042/BJ20140972

Experimental method

X-RAY DIFFRACTION (2 Å)