1G8P

CRYSTAL STRUCTURE OF BCHI SUBUNIT OF MAGNESIUM CHELATASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.214 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

Interplay between an AAA module and an integrin I domain may regulate the function of magnesium chelatase.

Fodje, M.N.Hansson, A.Hansson, M.Olsen, J.G.Gough, S.Willows, R.D.Al-Karadaghi, S.

(2001) J.Mol.Biol. 311: 111-122

  • DOI: 10.1006/jmbi.2001.4834

  • PubMed Abstract: 
  • In chlorophyll biosynthesis, insertion of Mg(2+) into protoporphyrin IX is catalysed in an ATP-dependent reaction by a three-subunit (BchI, BchD and BchH) enzyme magnesium chelatase. In this work we present the three-dimensional structure of the ATP- ...

    In chlorophyll biosynthesis, insertion of Mg(2+) into protoporphyrin IX is catalysed in an ATP-dependent reaction by a three-subunit (BchI, BchD and BchH) enzyme magnesium chelatase. In this work we present the three-dimensional structure of the ATP-binding subunit BchI. The structure has been solved by the multiple wavelength anomalous dispersion method and refined at 2.1 A resolution to the crystallographic R-factor of 22.2 % (R(free)=24.5 %). It belongs to the chaperone-like "ATPase associated with a variety of cellular activities" (AAA) family of ATPases, with a novel arrangement of domains: the C-terminal helical domain is located behind the nucleotide-binding site, while in other known AAA module structures it is located on the top. Examination by electron microscopy of BchI solutions in the presence of ATP demonstrated that BchI, like other AAA proteins, forms oligomeric ring structures. Analysis of the amino acid sequence of subunit BchD revealed an AAA module at the N-terminal portion of the sequence and an integrin I domain at the C terminus. An acidic, proline-rich region linking these two domains is suggested to contribute to the association of BchI and BchD by binding to a positively charged cleft at the surface of the nucleotide-binding domain of BchI. Analysis of the amino acid sequences of BchI and BchH revealed integrin I domain-binding sequence motifs. These are proposed to bind the integrin I domain of BchD during the functional cycle of magnesium chelatase, linking porphyrin metallation by BchH to ATP hydrolysis by BchI. An integrin I domain and an acidic and proline-rich region have been identified in subunit CobT of cobalt chelatase, clearly demonstrating its homology to BchD. These findings, for the first time, provide an insight into the subunit organisation of magnesium chelatase and the homologous colbalt chelatase.


    Organizational Affiliation

    Department of Molecular Biophysics, Lund University, Lund, 221 00, Sweden.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
MAGNESIUM-CHELATASE 38 KDA SUBUNIT
A
350Rhodobacter capsulatus (strain ATCC BAA-309 / NBRC 16581 / SB1003)Mutation(s): 0 
Gene Names: bchI
EC: 6.6.1.1
Find proteins for P26239 (Rhodobacter capsulatus (strain ATCC BAA-309 / NBRC 16581 / SB1003))
Go to UniProtKB:  P26239
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.214 
  • Space Group: P 65
Unit Cell:
Length (Å)Angle (°)
a = 90.259α = 90.00
b = 90.259β = 90.00
c = 83.716γ = 120.00
Software Package:
Software NamePurpose
DENZOdata reduction
CNSphasing
SCALEPACKdata scaling
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-08-03
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2014-11-12
    Type: Structure summary
  • Version 1.4: 2018-03-07
    Type: Data collection