1Q9S

Crystal structure of riboflavin kinase with ternary product complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.42 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.199 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Ligand binding-induced conformational changes in riboflavin kinase: structural basis for the ordered mechanism.

Karthikeyan, S.Zhou, Q.Osterman, A.L.Zhang, H.

(2003) Biochemistry 42: 12532-12538

  • DOI: 10.1021/bi035450t

  • PubMed Abstract: 
  • Riboflavin kinase (RFK) is an essential enzyme catalyzing the phosphorylation of riboflavin (vitamin B(2)) in the presence of ATP and Mg(2+) to form the active cofactor FMN, which can be further converted to FAD. Previously, the crystal structures of ...

    Riboflavin kinase (RFK) is an essential enzyme catalyzing the phosphorylation of riboflavin (vitamin B(2)) in the presence of ATP and Mg(2+) to form the active cofactor FMN, which can be further converted to FAD. Previously, the crystal structures of RFKs from human and Schizosaccharomyces pombe have been determined in the apo form and in complex with MgADP. These structures revealed that RFK adopts a novel kinase fold and utilizes a unique nucleotide binding site. The structures of the flavin-bound RFK obtained by soaking pre-existing crystals were also reported. Because of crystal packing restraints, these flavin-bound RFK complexes adopt conformations nearly identical with that of corresponding flavin-free structures. Here we report the structure of human RFK cocrystallized with both MgADP and FMN. Drastic conformational changes associated with flavin binding are observed primarily at the so-called Flap I and Flap II loop regions. As a result, the bound FMN molecule now interacts with the enzyme extensively and is well-ordered. Residues from Flap II interact with Flap I and shield the FMN molecule from the solvent. The conformational changes in Flap I resulted in a new Mg(2+) coordination pattern in which a FMN phosphate oxygen and Asn36 side chain carbonyl are directly coordinating to the Mg(2+) ion. The proposed catalytic base Glu86 is well-positioned for activation of the O5' hydroxyl group of riboflavin for the phosphoryl transfer reaction. The structural data obtained so far on human and yeast RFK complexes provide a rationale for the ordered kinetic mechanism of RFK.


    Organizational Affiliation

    Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
hypothetical protein FLJ11149
A
149Homo sapiensMutation(s): 0 
Gene Names: RFK
EC: 2.7.1.26
Find proteins for Q969G6 (Homo sapiens)
Go to Gene View: RFK
Go to UniProtKB:  Q969G6
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FMN
Query on FMN

Download SDF File 
Download CCD File 
A
FLAVIN MONONUCLEOTIDE
RIBOFLAVIN MONOPHOSPHATE
C17 H21 N4 O9 P
FVTCRASFADXXNN-SCRDCRAPSA-N
 Ligand Interaction
ADP
Query on ADP

Download SDF File 
Download CCD File 
A
ADENOSINE-5'-DIPHOSPHATE
C10 H15 N5 O10 P2
XTWYTFMLZFPYCI-KQYNXXCUSA-N
 Ligand Interaction
MG
Query on MG

Download SDF File 
Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.42 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.199 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 76.312α = 90.00
b = 118.789β = 90.00
c = 37.979γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
AMoREphasing
CNSrefinement
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-12-16
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance