1GKA

The molecular basis of the coloration mechanism in lobster shell. beta-crustacyanin at 3.2 A resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.23 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.213 

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This is version 1.3 of the entry. See complete history


Literature

The Molecular Basis of the Coloration Mechanism in Lobster Shell: Beta -Crustacyanin at 3.2-A Resolution

Cianci, M.Rizkallah, P.Olczak, A.Raftery, J.Chayen, N.Zagalsky, P.Helliwell, J.

(2002) Proc Natl Acad Sci U S A 99: 9795

  • DOI: https://doi.org/10.1073/pnas.152088999
  • Primary Citation of Related Structures:  
    1GKA

  • PubMed Abstract: 

    The binding of the carotenoid astaxanthin (AXT) in the protein multimacromolecular complex crustacyanin (CR) is responsible for the blue coloration of lobster shell. The structural basis of the bathochromic shift mechanism has long been elusive. A change in color occurs from the orange red of the unbound dilute AXT (lambda(max) 472 nm in hexane), the well-known color of cooked lobster, to slate blue in the protein-bound live lobster state (lambda(max) 632 nm in CR). Intriguingly, extracted CR becomes red on dehydration and on rehydration goes back to blue. Recently, the innovative use of softer x-rays and xenon derivatization yielded the three-dimensional structure of the A(1) apoprotein subunit of CR, confirming it as a member of the lipocalin superfamily. That work provided the molecular replacement search model for a crystal form of the beta-CR holo complex, that is an A(1) with A(3) subunit assembly including two bound AXT molecules. We have thereby determined the structure of the A(3) molecule de novo. Lobster has clearly evolved an intricate structural mechanism for the coloration of its shell using AXT and a bathochromic shift. Blue/purple AXT proteins are ubiquitous among invertebrate marine animals, particularly the Crustacea. The three-dimensional structure of beta-CR has identified the protein contacts and structural alterations needed for the AXT color regulation mechanism.


  • Organizational Affiliation

    Department of Chemistry, University of Manchester, Manchester M13 9PL, United Kingdom.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CRUSTACYANIN A1 SUBUNIT180Homarus gammarusMutation(s): 0 
UniProt
Find proteins for P58989 (Homarus gammarus)
Explore P58989 
Go to UniProtKB:  P58989
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP58989
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
CRUSTACYANIN A2 SUBUNIT174Homarus gammarusMutation(s): 0 
UniProt
Find proteins for P80007 (Homarus gammarus)
Explore P80007 
Go to UniProtKB:  P80007
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP80007
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.23 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.213 
  • R-Value Observed: 0.213 
  • Space Group: P 63 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 155.466α = 90
b = 155.466β = 90
c = 168.504γ = 120
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-08-08
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description