A novel interdomain interface in crystallins: structural characterization of the beta gamma-crystallin from Geodia cydonium at 0.99 angstrom resolution

作者:Vergara Alessandro; Grassi Marco; Sica Filomena; Pizzo Elio; D' Alessio Giuseppe; Mazzarella Lelio; Merlino Antonello*
来源:Acta Crystallographica Section D-Biological Crystallography, 2013, 69(6): 960-967.
DOI:10.1107/S0907444913003569

摘要

The beta gamma-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 beta gamma-crystallins that constitute the vertebrate eye lens. This study reports the crystallographic structure at 0.99 angstrom resolution of the two-domain beta gamma-crystallin (geodin) from the sponge Geodia cydonium. This is the most ancient member of the beta gamma-crystallin superfamily in metazoans. The X-ray structure shows that the geodin domains adopt the typical beta gamma-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.

  • 出版日期2013-6