1O8Q

The active site of the molybdenum cofactor biosenthetic protein domain Cnx1G


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.193 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The Active Site of the Molybdenum Cofactor Biosynthetic Protein Domain Cnx1G

Kuper, J.Winking, J.Hecht, H.J.Mendel, R.R.Schwarz, G.

(2003) Arch.Biochem.Biophys. 411: 36

  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The final step of molybdenum cofactor biosynthesis in plants is catalyzed by the two-domain protein Cnx1. The G domain of Cnx1 (Cnx1G) binds molybdopterin with high affinity and transfers molybdenum to molybdopterin. Here, we describe the functional ...

    The final step of molybdenum cofactor biosynthesis in plants is catalyzed by the two-domain protein Cnx1. The G domain of Cnx1 (Cnx1G) binds molybdopterin with high affinity and transfers molybdenum to molybdopterin. Here, we describe the functional and structural characterization of structure-based Cnx1G mutants. For molybdopterin binding residues Thr542 and Ser573 were found to be important because different mutations of those residues resulted in 7- to 26-fold higher k(D) values for molybdopterin binding. Furthermore, we showed that the terminal phosphate of molybdopterin is directly involved in protein-pterin interactions as dephosphorylated molybdopterin binds with one magnitude of order lower affinity to the wild-type protein. Molybdopterin binding was not affected in mutants defective in Ser476, Asp486, or Asp515. However, molybdenum insertion was completely abolished, indicating their important role for catalysis. Based on these results we propose the binding of molybdopterin to a large depression in the structure of Cnx1G formed by beta5, alpha5, beta6, and alpha6, whereas the negatively charged depression formed by the loop between beta3 and alpha4, the N-terminal end of alpha2, the 3(10) helix, and the region between beta6 and alpha6 is involved in catalysis.


    Organizational Affiliation

    Department of Plant Biology, Technical University of Braunschweig, 38028, Braunschweig, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
MOLYBDOPTERIN BIOSYNTHESIS CNX1 PROTEIN
A, B, C, D, E, F, G, H
167Arabidopsis thalianaMutation(s): 1 
Gene Names: CNX1
EC: 2.10.1.1, 2.7.7.75
Find proteins for Q39054 (Arabidopsis thaliana)
Go to UniProtKB:  Q39054
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.193 
  • Space Group: P 21 3
Unit Cell:
Length (Å)Angle (°)
a = 174.610α = 90.00
b = 174.610β = 90.00
c = 174.610γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
REFMACrefinement
AMoREphasing
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-02-27
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance