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Publication Abstract from PubMed

The betagamma-crystallin superfamily includes highly diverse proteins belonging to all of the kingdoms of life. Based on structural topology, these proteins are considered to be evolutionarily related to the long-lived betagamma-crystallins that constitute the vertebrate eye lens. This study reports the crystallographic structure at 0.99 A resolution of the two-domain betagamma-crystallin (geodin) from the sponge Geodia cydonium. This is the most ancient member of the betagamma-crystallin superfamily in metazoans. The X-ray structure shows that the geodin domains adopt the typical betagamma-crystallin fold with a paired Greek-key motif, thus confirming the hypothesis that the crystallin-type scaffold used in the evolution of bacteria and moulds was recruited very early in metazoans. As a significant new structural feature, the sponge protein possesses a unique interdomain interface made up by pairing between the second motif of the first domain and the first motif of the second domain. The atomic resolution also allowed a detailed analysis of the calcium-binding site of the protein.

A novel interdomain interface in crystallins: structural characterization of the betagamma-crystallin from Geodia cydonium at 0.99 A resolution.,Vergara A, Grassi M, Sica F, Pizzo E, D'Alessio G, Mazzarella L, Merlino A Acta Crystallogr D Biol Crystallogr. 2013 Jun;69(Pt 6):960-7. doi:, 10.1107/S0907444913003569. Epub 2013 May 2. PMID:23695240^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.