4ZHJ

Crystal Structure of the Catalytic Subunit of Magnesium Chelatase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 

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This is version 1.1 of the entry. See complete history


Literature

Crystal structure of the catalytic subunit of magnesium chelatase

Chen, X.Pu, H.Fang, Y.Wang, X.Zhao, S.Lin, Y.Zhang, M.Dai, H.E.Gong, W.Liu, L.

(2015) Nat Plants 1: 15125-15125

  • DOI: 10.1038/nplants.2015.125
  • Primary Citation of Related Structures:  
    4ZHJ

  • PubMed Abstract: 
  • Tetrapyrroles, including haem and chlorophyll, play vital roles for various biological processes, such as respiration and photosynthesis, and their biosynthesis is critical for virtually all organisms. In photosynthetic organisms, magnesium chelatase (MgCh) catalyses insertion of magnesium into the centre of protoporphyrin IX, the branch-point precursor for both haem and chlorophyll, leading tetrapyrrole biosynthesis into the magnesium branch(1,2) ...

    Tetrapyrroles, including haem and chlorophyll, play vital roles for various biological processes, such as respiration and photosynthesis, and their biosynthesis is critical for virtually all organisms. In photosynthetic organisms, magnesium chelatase (MgCh) catalyses insertion of magnesium into the centre of protoporphyrin IX, the branch-point precursor for both haem and chlorophyll, leading tetrapyrrole biosynthesis into the magnesium branch(1,2). This reaction needs a cooperated action of the three subunits of MgCh: the catalytic subunit ChlH and two AAA(+) subunits, ChlI and ChlD (refs 3-5). To date, the mechanism of MgCh awaits further elucidation due to a lack of high-resolution structures, especially for the ∼150 kDa catalytic subunit. Here we report the crystal structure of ChlH from the photosynthetic cyanobacterium Synechocystis PCC 6803, solved at 2.5 Å resolution. The active site is buried deeply inside the protein interior, and the surrounding residues are conserved throughout evolution. This structure helps to explain the loss of function reported for the cch and gun5 mutations of the ChlH subunit, and to provide the molecular basis of substrate channelling during the magnesium-chelating process. The structure advances our understanding of the holoenzyme of MgCh, a metal chelating enzyme other than ferrochelatase.


    Organizational Affiliation

    Photosynthesis Research Centre, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Mg-chelatase subunit ChlHA, B1351Synechocystis sp. PCC 6803 substr. KazusaMutation(s): 0 
Gene Names: chlH
EC: 6.6.1.1
UniProt
Find proteins for P73020 (Synechocystis sp. (strain PCC 6803 / Kazusa))
Explore P73020 
Go to UniProtKB:  P73020
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 319.717α = 90
b = 319.717β = 90
c = 105.194γ = 120
Software Package:
Software NamePurpose
HKL-2000data collection
SCALEPACKdata scaling
SHELXphasing
PHENIXrefinement
PDB_EXTRACTdata extraction
HKL-2000data reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-08-26
    Type: Initial release
  • Version 1.1: 2016-06-15
    Changes: Database references