The crystal structure of lobster apocrustacyanin A1 using softer X-rays.

Experimental Data Snapshot

  • Resolution: 1.40 Å
  • R-Value Free: 0.229 
  • R-Value Observed: 0.177 

wwPDB Validation   3D Report Full Report

This is version 1.4 of the entry. See complete history


Structure of Lobster Apocrustacyanin A1 Using Softer X-Rays

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

(2001) Acta Crystallogr D Biol Crystallogr 57: 1219

  • DOI: https://doi.org/10.1107/s0907444901009350
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The molecular basis of the camouflage colouration of marine crustacea is often provided by carotenoproteins. The blue colour of the lobster carapace, for example, is intricately associated with a multimacromolecular 16-mer complex of protein subunits each with a bound astaxanthin molecule. The protein subunits of crustacyanin fall into two distinct subfamilies, CRTC and CRTA. Here, the crystal structure solution of the A(1) protein of the CRTC subfamily is reported. The problematic nature of the structure solution of the CRTC proteins (both C(1) and A(1)) warranted consideration and the development of new approaches. Three putative disulfides per protein subunit were likely to exist based on molecular-homology modelling against known lipocalin protein structures. With two such subunits per crystallographic asymmetric unit, this direct approach was still difficult as it involved detecting a weak signal from these sulfurs and suggested the use of softer X-rays, combined with high data multiplicity, as reported previously [Chayen et al. (2000), Acta Cryst. D56, 1064-1066]. This paper now describes the structure solution of CRTC in the form of the A(1) dimer based on use of softer X-rays (2 A wavelength). The structure solution involved a xenon derivative with an optimized xenon L(I) edge f" signal and a native data set. The hand of the xenon SIROAS phases was determined by using the sulfur anomalous signal from a high-multiplicity native data set also recorded at 2 A wavelength. For refinement, a high-resolution data set was measured at short wavelength. All four data sets were collected at 100 K. The refined structure to 1.4 A resolution based on 60 276 reflections has an R factor of 17.7% and an R(free) of 22.9% (3137 reflections). The structure is that of a typical lipocalin, being closely related to insecticyanin, to bilin-binding protein and to retinol-binding protein. This A(1) monomer or dimer can now be used as a search motif in the structural studies of the oligomeric forms alpha- and beta-crustacyanins, which contain bound astaxanthin molecules.

  • Organizational Affiliation

    Department of Chemistry, University of Manchester, Manchester M13 9PL, England.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
180Homarus gammarusMutation(s): 0 
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
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.40 Å
  • R-Value Free: 0.229 
  • R-Value Observed: 0.177 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 41.65α = 90
b = 80.68β = 90
c = 110.84γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-09-06
    Type: Initial release
  • Version 1.1: 2011-05-07
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2019-05-08
    Changes: Advisory, Data collection, Derived calculations, Experimental preparation, Other
  • Version 1.4: 2019-05-22
    Changes: Data collection, Refinement description