The Crystal Structure of RosB: Insights into the Reaction Mechanism of the First Member of a Family of Flavodoxin‐like Enzymes. Issue 4 (16th December 2016)

• Record Type: Journal Article
• Authors: Konjik, Valentino; Brünle, Steffen; Demmer, Ulrike; Vanselow, Amanda; Sandhoff, Roger; Ermler, Ulrich; Mack, Matthias
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 4(2017)
• Page Start: 1146
• Page End: 1151
• Publication Date: 2016-12-16
• Subjects: AFP synthase -- RosB -- roseoflavin -- Streptomyces davawensis; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201610292
• Languages: English
• ISSNs: 1433-7851

Abstract

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 (HO2 C‐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. Abstract : Team work : Structural analysis of RosB from Streptomyces davawensis reveals a flavodoxin‐like protein in which specialized linkers and a unique C‐terminal arm synergistically act to catalyze a unique multi‐step oxidative cascade reaction leading to the key intermediate of roseoflavin synthesis.