Interdomain electron transfer in flavohaemoglobin from Candida norvegensis with antibiotic azole compounds

FEBS Letters

article

Kazuo Kobayashi¹  Jotaro Igarashi²  Takahiro Kozawa¹ 

[1] The Institute of Scientific and Industrial Research, Osaka University;Fukushima Medical University

关键词: electron transfer;    flavohaemoglobin;    nitric oxide dioxygenase;    pulse radiolysis;   

DOI  :  10.1002/1873-3468.14327

来源: John Wiley & Sons Ltd.

【 摘 要 】

Flavohaemoglobins (FlavoHbs) function as nitric oxide dioxygenases, oxidizing nitric oxide with nitrite and shuttling electrons from NAD(P)H via FAD and O 2 . Here, using pulse radiolysis, we investigate intramolecular electron transfer between FAD and haem b in FlavoHbs. We found that reduction of FlavoHb with hydrated electrons proceeded via two phases: an initial fast phase and a second slower process. Absorbance measured at 600 nm revealed fast flavin reduction followed by a slower decrease corresponding to reoxidation of FAD. The slower process was partially lost in FlavoHbs lacking FAD. These results suggest that the slower phase is attributable to intramolecular electron transfer from FAD to the haem iron. The rate constant in the absence of azole compound (3.3 × 10 3  s -1 ) was accelerated ~ 10-fold (2.7 × 10 4  s -1 ) by the binding of econazole, reflecting a conformational change in the open-to-closed transition.

【 授权许可】

Unknown