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Preparation and characterization of geodin
Author(s) -
Giancola Concetta,
Pizzo Elio,
Di Maro Antimo,
Cubellis Maria Vittoria,
D'Alessio Giuseppe
Publication year - 2005
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2004.04536.x
Subject(s) - escherichia coli , superfamily , crystallin , biology , homology (biology) , phylogenesis , gene , biochemistry , homology modeling , recombinant dna , subfamily , genetics , chemistry , phylogenetics , enzyme
Geodin is a protein encoded by a sponge gene homologous to genes from the βγ‐crystallins superfamily. The interest for this crystallin‐type protein stems from the phylogenesis of porifera, commonly called sponges, the earliest divergence event in the history of metazoans. Here we report the preparation of geodin as a recombinant protein from Escherichia coli , its characterization through physico‐chemical analyses, and a model of its 3D structure based on homology modelling. Geodin is a monomeric protein of about 18 kDa, with an all‐beta structure, as all other crystallins in the superfamily, but more prone to unfold in the presence of chemical denaturants, when compared with other homologues from the superfamily. Its thermal unfolding, studied by far‐ and near‐CD, and by calorimetry, is described by a two‐state model. Geodin appears to be structurally similar in many respects to the bacterial protein S crystallin, with which it also shares a significant, albeit more modest stabilizing effect exerted by calcium ions. These results suggest that the crystallin‐type structural scaffold, employed in the evolution of bacteria and moulds, was successfully recruited very early in the evolution of metazoa.