1BLB

CLOSE PACKING OF AN OLIGOMERIC EYE LENS BETA-CRYSTALLIN INDUCES LOSS OF SYMMETRY AND ORDERING OF SEQUENCE EXTENSIONS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.30 Å

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Close packing of an oligomeric eye lens beta-crystallin induces loss of symmetry and ordering of sequence extensions.

Nalini, V.Bax, B.Driessen, H.Moss, D.S.Lindley, P.F.Slingsby, C.

(1994) J Mol Biol 236: 1250-1258

  • DOI: https://doi.org/10.1016/0022-2836(94)90025-6
  • Primary Citation of Related Structures:  
    1BLB

  • PubMed Abstract: 

    beta-Crystallins are oligomeric eye lens proteins that are related to monomeric gamma-crystallins. The main sequence difference between the two families is the presence of sequence extensions in the beta-crystallins. A major question concerns the role that these extensions play in mediating interactions at the high protein concentrations found in the lens. The predominant beta-crystallin polypeptide, beta B2, can be crystallized in two different space groups, I222 and C222. The I222 crystal structure revealed that the protein packed as a tetramer with perfect 222 symmetry but that the extensions were disordered. The X-ray structure of the C222 lattice of beta B2 has now been refined at 3.3 A, the structure analysed and compared with the I222 lattice. The protein is also a tetramer with 222 symmetry in the C222 lattice but differs in that parts of the N-terminal extensions have been visualized. In the asymmetric unit of the C222 lattice there are four subunits, each comprising a single polypeptide chain, in which certain flexible loops in the N-terminal domains and the N-terminal extensions have various conformations. The tetramers in the C222 lattice are more tightly packed than in the I222 form. Analysis of the tetramer contacts shows that the sites of interaction break the 222 symmetry of the tetramers. The N-terminal extensions play a major role in directing interactions between tetramers. One of the N-terminal extensions interacts with a hydrophobic patch on the N-terminal domain of another tetramer. These crystallographic observations obtained over a physiological concentration range indicate how, in beta-crystallin oligomers, the N-terminal extensions of beta B2 can switch from interacting with water to interacting with protein depending on their relative concentrations. This could be useful in maintaining a gradient of refractive index.


  • Organizational Affiliation

    Laboratory of Molecular Biology, Birkbeck College, London University, UK.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
BETA B2-CRYSTALLIN
A, B, C, D
204Bos taurusMutation(s): 0 
UniProt
Find proteins for P02522 (Bos taurus)
Explore P02522 
Go to UniProtKB:  P02522
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02522
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.30 Å
  • Space Group: C 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 154.71α = 90
b = 165.9β = 90
c = 78.48γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
RESTRAINrefinement
X-PLORrefinement
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1994-12-20
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-02-07
    Changes: Data collection, Database references, Other