2ISK

BluB bound to flavin anion (charge transfer complex)

2ISK の概要

• エントリーDOI: 10.2210/pdb2isk/pdb
• 関連するPDBエントリー: 2ISJ 2ISL
• 分子名称: BluB, 1-DEOXY-1-(7,8-DIMETHYL-2,4-DIOXO-3,4-DIHYDRO-2H-BENZO[G]PTERIDIN-1-ID-10(5H)-YL)-5-O-PHOSPHONATO-D-RIBITOL (3 entities in total)
• 機能のキーワード: oxidoreductase, flavin, monooxygenase, flavin destructase, vitamin b12, dithionite, charge transfer complex, flavoprotein
• 由来する生物種: Sinorhizobium meliloti
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 210229.83

構造登録者

Larsen, N.A.,Taga, M.E.,Howard-Jones, A.R.,Walsh, C.T.,Walker, G.C. (登録日: 2006-10-17, 公開日: 2007-03-27, 最終更新日: 2024-02-21)

主引用文献

Taga, M.E.,Larsen, N.A.,Howard-Jones, A.R.,Walsh, C.T.,Walker, G.C.
BluB cannibalizes flavin to form the lower ligand of vitamin B12.
Nature, 446:449-453, 2007

PubMed Abstract: Vitamin B12 (cobalamin) is among the largest known non-polymeric natural products, and the only vitamin synthesized exclusively by microorganisms. The biosynthesis of the lower ligand of vitamin B(12), 5,6-dimethylbenzimidazole (DMB), is poorly understood. Recently, we discovered that a Sinorhizobium meliloti gene, bluB, is necessary for DMB biosynthesis. Here we show that BluB triggers the unprecedented fragmentation and contraction of the bound flavin mononucleotide cofactor and cleavage of the ribityl tail to form DMB and D-erythrose 4-phosphate. Our structural analysis shows that BluB resembles an NAD(P)H-flavin oxidoreductase, except that its unusually tight binding pocket accommodates flavin mononucleotide but not NAD(P)H. We characterize crystallographically an early intermediate along the reaction coordinate, revealing molecular oxygen poised over reduced flavin. Thus, BluB isolates and directs reduced flavin to activate molecular oxygen for its own cannibalization. This investigation of the biosynthesis of DMB provides clarification of an aspect of vitamin B12 that was otherwise incomplete, and may contribute to a better understanding of vitamin B12-related disease.

PubMed: 17377583
DOI: 10.1038/nature05611

実験手法

X-RAY DIFFRACTION (2.1 Å)