title: Convenient synthesis of deazaflavin cofactor FO and its activity in F(420)-dependent NADP reductase.
abstract: F420 and FO are phenolic 5-deazaflavin cofactors that complement nicotinamide and flavin redox coenzymes in biochemical oxidoreductases and photocatalytic systems. Specifically, these 5-deazaflavins lack the single electron reactivity with O2 of riboflavin-derived coenzymes (FMN and FAD), and, in general, have a more negative redox potential than NAD(P)(+). For example, F420-dependent NADP(+) oxidoreductase (Fno) is critical to the conversion of CO2 to CH4 by methanogenic archaea, while FO functions as a light-harvesting agent in DNA repair. The preparation of these cofactors is an obstacle to their use in biochemical studies and biotechnology. Here, a convenient synthesis of FO was achieved by improving the redox stability of synthetic intermediates containing a polar, electron-rich aminophenol fragment. Improved yields and simplified purification techniques for FO are described. Additionally, Fno activity was restored with FO in the absence of F420. Investigating the FO-dependent NADP(+)/NADPH redox process by stopped-flow spectrophotometry, steady state kinetics were defined as having a Km of 4.00 ± 0.39 μM and a kcat of 5.27 ± 0.14 s(-1). The preparation of FO should enable future biochemical studies and novel uses of F420 mimics.
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Arlington, 700 Planetarium Place, Arlington, TX 76019, USA. ffoss@uta.edu kayunta@uta.edu.
authors.forename: Mohammad S
authors.initials: MS
authors.lastname: Hossain
authors.forename: Cuong Q
authors.initials: CQ
authors.lastname: Le
authors.forename: Ebenezer
authors.initials: E
authors.lastname: Joseph
authors.forename: Toan Q
authors.initials: TQ
authors.lastname: Nguyen
authors.forename: Kayunta
authors.initials: K
authors.lastname: Johnson-Winters
authors.forename: Frank W
authors.initials: FW
authors.lastname: Foss
mesh_terms: D009249:NADP / Q000737:chemistry*; D010088:Oxidoreductases / Q000737:chemistry*; D012256:Riboflavin / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: C007701:factor 420; D009249:NADP; D010088:Oxidoreductases; D012256:Riboflavin