The E-configuration of alfa-Phycoerythrocyanin

Experimental Data Snapshot

  • Resolution: 2.25 Å
  • R-Value Free: 0.309 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.235 

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This is version 1.4 of the entry. See complete history


Structural Basis for the Photochemistry of Alfa-Phycoerythrocyanin

Schmidt, M.Patel, A.Zhao, Y.Reuter, W.

(2007) Biochemistry 46: 416

  • DOI: https://doi.org/10.1021/bi061844j
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Phycobiliproteins and phytochromes are light-harvesting and light-sensing proteins containing linear tetrapyrroles, so-called bile chromophores. The chromophores in certain biliproteins, including the phytochromes, isomerize reversibly from a stable Z-configuration to a stable E-configuration when irradiated with light of the appropriate wavelength. Here, we report the crystal structure of alpha-phycoerythrocyanin with its chromophore in the E-configuration, compare it with the Z-configuration found in trimeric phycoerythrocyanin, and reveal the structural bases of the isomerization. The geometric changes of the chromophore account for the large spectral shift, which characterizes the overall transition. Interactions of the chromophore A and D pyrrole rings with flexible protein moieties are required for the formation and stabilization of the isomers. We predict that the results will hold for all photoactive biliproteins.

  • Organizational Affiliation

    Physikdepartment E17, Technische Universität München, James Franck Strasse, 85747 Garching, Germany. marius.schmidt@ph.tum.de

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
162Mastigocladus laminosusMutation(s): 0 
Find proteins for P00309 (Mastigocladus laminosus)
Explore P00309 
Go to UniProtKB:  P00309
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00309
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on PVN

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
C33 H40 N4 O6
Experimental Data & Validation

Experimental Data

  • Resolution: 2.25 Å
  • R-Value Free: 0.309 
  • R-Value Work: 0.235 
  • R-Value Observed: 0.235 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 129.808α = 90
b = 102.598β = 94.48
c = 32.146γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-01-23
    Type: Initial release
  • Version 1.1: 2012-07-25
    Changes: Non-polymer description, Other, Version format compliance
  • Version 1.2: 2019-05-08
    Changes: Data collection, Derived calculations, Experimental preparation, Other
  • Version 1.3: 2019-07-24
    Changes: Data collection
  • Version 1.4: 2023-12-13
    Changes: Data collection, Database references, Derived calculations, Refinement description