title: Si-face stereospecificity at C5 of coenzyme F420 for F420H2 oxidase from methanogenic Archaea as determined by mass spectrometry.
abstract: Coenzyme F420 is a 5-deazaflavin. Upon reduction, 1,5 dihydro-coenzyme F420 is formed with a prochiral centre at C5. All the coenzyme F420-dependent enzymes investigated to date have been shown to be Si-face stereospecific with respect to C5 of the deazaflavin, despite most F420-dependent enzymes being unrelated phylogenetically. In this study, we report that the recently discovered F420H2 oxidase from methanogenic Archaea is also Si-face stereospecific. The enzyme was found to catalyse the oxidation of (5S)-[5-2H1]F420H2 with O2 to [5-1H]F420 rather than to [5-2H]F420 as determined by MALDI-TOF MS. (5S)-[5-2H1]F420H2 was generated by stereospecific enzymatic reduction of F420 with (14a-2H2)-[14a-2H2] methylenetetrahydromethanopterin.
authors.affiliation: Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Seedorf
authors.forename: Jörg
authors.initials: J
authors.lastname: Kahnt
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Pierik
authors.forename: Rudolf K
authors.initials: RK
authors.lastname: Thauer
mesh_terms: D019605:Euryarchaeota / Q000201:enzymology*; D005486:Flavin Mononucleotide / Q000737:chemistry; D015394:Molecular Structure; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry*; D010084:Oxidation-Reduction; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry; D011622:Pterins / Q000737:chemistry; D012256:Riboflavin / Q000031:analogs & derivatives* / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013237:Stereoisomerism
chemical_list: C091917:N(5),N(10)-methylene-tetrahydromethanopterin; D011622:Pterins; C011744:5-deaza-FMN; C015084:coenzyme F420; D005486:Flavin Mononucleotide; D000587:Oxidoreductases Acting on CH-NH Group Donors; C047126:methylenetetrahydromethanopterin dehydrogenase; D009247:NADH, NADPH Oxidoreductases; C109941:F420-dependent NADP reductase; D012256:Riboflavin