title: The Crystal Structure of RosB: Insights into the Reaction Mechanism of the First Member of a Family of Flavodoxin-like Enzymes.
abstract: 8-demethyl-8-aminoriboflavin-5'-phosphate (AFP) synthase (RosB) catalyzes the key reaction of roseoflavin biosynthesis by forming AFP from riboflavin-5'-phosphate (RP) and glutamate via the intermediates 8-demethyl-8-formylriboflavin-5'-phosphate (OHC-RP) and 8-demethyl-8-carboxylriboflavin-5'-phosphate (HO2C-RP). To understand this reaction in which a methyl substituent of an aromatic ring is replaced by an amine we structurally characterized RosB in complex with OHC-RP (2.0 Å) and AFP (1.7 Å). RosB is composed of four flavodoxin-like subunits which have been upgraded with specific extensions and a unique C-terminal arm. It appears that RosB has evolved from an electron- or hydride-transferring flavoprotein to a sophisticated multi-step enzyme which uses RP as a substrate (and not as a cofactor). Structure-based active site analysis was complemented by mutational and isotope-based mass-spectrometric data to propose an enzymatic mechanism on an atomic basis.
authors.affiliation: Mannheim University of Applied Sciences, Paul-Wittsack-Strasse 10, 68163, Mannheim, Germany.
authors.forename: Valentino
authors.initials: V
authors.lastname: Konjik
authors.affiliation: Max-Planck-Institute for Biophysics, Max-von-Laue-Strasse 3, 60438, Frankfurt am Main, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Brünle
authors.affiliation: Max-Planck-Institute for Biophysics, Max-von-Laue-Strasse 3, 60438, Frankfurt am Main, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Demmer
authors.affiliation: Mannheim University of Applied Sciences, Paul-Wittsack-Strasse 10, 68163, Mannheim, Germany.
authors.forename: Amanda
authors.initials: A
authors.lastname: Vanselow
authors.affiliation: German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
authors.forename: Roger
authors.initials: R
authors.lastname: Sandhoff
authors.affiliation: Max-Planck-Institute for Biophysics, Max-von-Laue-Strasse 3, 60438, Frankfurt am Main, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Ermler
authors.affiliation: Mannheim University of Applied Sciences, Paul-Wittsack-Strasse 10, 68163, Mannheim, Germany.
authors.forename: Matthias
authors.identifier: 0000-0002-7753-2422
authors.initials: M
authors.lastname: Mack
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D055162:Biocatalysis; D018360:Crystallography, X-Ray; D013058:Mass Spectrometry; D008958:Models, Molecular; D011487:Protein Conformation; D012256:Riboflavin / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000737:chemistry; D000637:Transaminases / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C023644:8-amino-8-demethylriboflavin; D000637:Transaminases; C000628653:RosB protein, Streptomyces davawensis; D012256:Riboflavin
keywords: AFP synthase; RosB; Streptomyces davawensis; roseoflavin