Crystal Structure of Human Riboflavin Kinase
[RIFK_HUMAN] Catalyzes the phosphorylation of riboflavin (vitamin B2) to form flavin-mononucleotide (FMN), hence rate-limiting enzyme in the synthesis of FAD. Essential for TNF-induced reactive oxygen species (ROS) production. Through its interaction with both TNFRSF1A and CYBA, physically and functionally couples TNFRSF1A to NADPH oxidase. TNF-activation of RFK may enhance the incorporation of FAD in NADPH oxidase, a critical step for the assembly and activation of NADPH oxidase.
Publication Abstract from PubMed
Riboflavin kinase (RFK) is an essential enzyme catalyzing the phosphorylation of riboflavin (vitamin B(2)) to form FMN, an obligatory step in vitamin B(2) utilization and flavin cofactor synthesis. The structure of human RFK revealed a six-stranded antiparallel beta barrel core structurally similar to the riboflavin synthase/ferredoxin reductase FAD binding domain fold. The binding site of an intrinsically bound MgADP defines a novel nucleotide binding motif that encompasses a loop, a 3(10) helix, and a reverse turn followed by a short beta strand. This active site loop forms an arch with ATP and riboflavin binding at the opposite side and the phosphoryl transfer appears to occur through the hole underneath the arch. The invariant residues Asn36 and Glu86 are implicated in the catalysis.
Crystal structure of human riboflavin kinase reveals a beta barrel fold and a novel active site arch.,Karthikeyan S, Zhou Q, Mseeh F, Grishin NV, Osterman AL, Zhang H Structure. 2003 Mar;11(3):265-73. PMID:12623014
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.