3IAJ image
Entry Detail
PDB ID:
3IAJ
Title:
Crystal structure of a betagamma-crystallin domain from Clostridium beijerinckii-in alternate space group I422
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2009-07-14
Release Date:
2009-12-01
Method Details:
Experimental Method:
Resolution:
2.10 Å
R-Value Free:
0.25
R-Value Work:
0.22
Space Group:
I 4 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Beta and gamma crystallin
Chain IDs:A
Chain Length:87
Number of Molecules:1
Biological Source:Clostridium beijerinckii
Ligand Molecules
Primary Citation
betagamma-Crystallin superfamily contains a universal motif for binding calcium.
Biochemistry ? ? ? (2009)
PMID: 19921810 DOI: 10.1021/bi9017076

Abstact

The betagamma-crystallin superfamily consists of evolutionarily related proteins with domain topology similar to lens beta- and gamma-crystallins, formed from duplicated Greek key motifs. Ca(2+) binding was found in a few betagamma-crystallin members earlier, although its prevalence and diversity as inherent molecular properties among members of the superfamily are not well studied. To increase our understanding of Ca(2+) binding in various betagamma-crystallins, we undertook comprehensive structural and Ca(2+)-binding studies of seven members of the superfamily from bacteria, archaea, and vertebrates, including determination of high-resolution crystal structures of three proteins. Our structural observations show that the determinants of Ca(2+) coordination remain conserved in the form of an N/D-N/D-#-I-S/T-S motif in all domains. However, binding of Ca(2+) elicits varied physicochemical responses, ranging from passive sequestration to active stabilization. The motif in this superfamily is modified in some members like lens crystallins where Ca(2+)-binding abilities are partly or completely compromised. We show that reduction or loss of Ca(2+) binding in members of the superfamily, particularly in vertebrates, is due to the selective presence of unfavorable amino acids (largely Arg) at key Ca(2+)-ligation positions and that engineering of the canonical Ca(2+)-binding residues can confer binding activity on an otherwise inactive domain. Through this work, we demonstrate that betagamma-crystallins with the N/D-N/D-#-I-S/T-S motif form an extensive set of Ca(2+)-binding proteins prevalent in all of the three kingdoms of life.

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Primary Citation of related structures