2ISJ

BluB bound to oxidized FMN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.207 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

BluB cannibalizes flavin to form the lower ligand of vitamin B12.

Taga, M.E.Larsen, N.A.Howard-Jones, A.R.Walsh, C.T.Walker, G.C.

(2007) Nature 446: 449-453

  • DOI: 10.1038/nature05611
  • Primary Citation of Related Structures:  

  • 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 under ...

    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.


    Organizational Affiliation

    Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
BluB
A, B, C, D, E, F, G, H
230Rhizobium meliloti (strain 1021)Mutation(s): 0 
Gene Names: bluB
EC: 1.13.11.79
Find proteins for Q92PC8 (Rhizobium meliloti (strain 1021))
Go to UniProtKB:  Q92PC8
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FMN
Query on FMN

Download SDF File 
Download CCD File 
A, B, C, D, E, F, G, H
FLAVIN MONONUCLEOTIDE
RIBOFLAVIN MONOPHOSPHATE
C17 H21 N4 O9 P
FVTCRASFADXXNN-SCRDCRAPSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
FMNKi: 231000 nM BINDINGMOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.207 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 65.149α = 90.00
b = 172.724β = 90.06
c = 92.063γ = 90.00
Software Package:
Software NamePurpose
MOLREPphasing
HKL-2000data collection
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-03-27
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance