2BB2
X-RAY ANALYSIS OF BETA B2-CRYSTALLIN AND EVOLUTION OF OLIGOMERIC LENS PROTEINS
Summary for 2BB2
Entry DOI | 10.2210/pdb2bb2/pdb |
Descriptor | BETA B2-CRYSTALLIN, BETA-MERCAPTOETHANOL (3 entities in total) |
Functional Keywords | eye lens protein |
Biological source | Bos taurus (cattle) |
Total number of polymer chains | 1 |
Total formula weight | 20897.27 |
Authors | Bax, B.,Lapatto, R.,Nalini, V.,Driessen, H.,Lindley, P.F.,Mahadevan, D.,Blundell, T.L.,Slingsby, C. (deposition date: 1992-09-21, release date: 1993-10-31, Last modification date: 2024-06-05) |
Primary citation | Bax, B.,Lapatto, R.,Nalini, V.,Driessen, H.,Lindley, P.F.,Mahadevan, D.,Blundell, T.L.,Slingsby, C. X-ray analysis of beta B2-crystallin and evolution of oligomeric lens proteins. Nature, 347:776-780, 1990 Cited by PubMed Abstract: The beta, gamma-crystallins form a class of homologous proteins in the eye lens. Each gamma-crystallin comprises four topologically equivalent, Greek key motifs; pairs of motifs are organized around a local dyad to give domains and two similar domains are in turn related by a further local dyad. Sequence comparisons and model building predicted that hetero-oligomeric beta-crystallins also had internally quadruplicated subunits, but with extensions at the N and C termini, indicating that beta, gamma-crystallins evolved in two duplication steps from an ancestral protein folded as a Greek key. We report here the X-ray analysis at 2.1 A resolution of beta B2-crystallin homodimer which shows that the connecting peptide is extended and the two domains separated in a way quite unlike gamma-crystallin. Domain interactions analogous to those within monomeric gamma-crystallin are intermolecular and related by a crystallographic dyad in the beta B2-crystallin dimer. This shows how oligomers can evolve by conserving an interface rather than connectivity. A further interaction between dimers suggests a model for more complex aggregates of beta-crystallin in the lens. PubMed: 2234050DOI: 10.1038/347776a0 PDB entries with the same primary citation |
Experimental method | X-RAY DIFFRACTION (2.1 Å) |
Structure validation
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