Crystal structure of PsbQ polypeptide of photosystem II from higher plants

Experimental Data Snapshot

  • Resolution: 1.95 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.227 

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Crystal structure of the PsbQ protein of photosystem II from higher plants

Calderone, V.Trabucco, M.Vujicic, A.Battistutta, R.Giacometti, G.M.Andreucci, F.Barbato, R.Zanotti, G.

(2003) EMBO Rep 4: 900-905

  • DOI: https://doi.org/10.1038/sj.embor.embor923
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The smallest extrinsic polypeptide of the water-oxidizing complex (PsbQ) was extracted and purified from spinach (Spinacia oleracea) photosystem II (PSII) membranes. It was then crystallized in the presence of Zn(2+) and its structure was determined by X-ray diffraction at 1.95-A resolution using the multi-wavelength anomalous diffraction method, with the zinc as the anomalous scatterer. The crystal structure shows that the core of the protein is a four-helix bundle, whereas the amino-terminal portion, which possibly interacts with the photosystem core, is not visible in the crystal. The distribution of positive and negative charges on the protein surface might explain the ability of PsbQ to increase the binding of Cl(-) and Ca(2+) and make them available to PSII.

  • Organizational Affiliation

    Dipartimento di Chimica Organica e Centro Biopolimeri del CNR, Università di Padova, Via Marzolo 1, 35131 Padua, Italy.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Oxygen-evolving enhancer protein 3149Spinacia oleraceaMutation(s): 0 
Find proteins for P12301 (Spinacia oleracea)
Explore P12301 
Go to UniProtKB:  P12301
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP12301
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on ZN

Download Ideal Coordinates CCD File 
B [auth A]ZINC ION
Experimental Data & Validation

Experimental Data

  • Resolution: 1.95 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.227 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 50.282α = 90
b = 50.282β = 90
c = 94.067γ = 120
Software Package:
Software NamePurpose
MOSFLMdata reduction
CCP4data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-08-26
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-02-14
    Changes: Data collection, Database references, Derived calculations