Authors: Verónica De Pino Cristina Marino Busjle Silvia Moreno
Publish Date: 2012/02/25
Volume: 250, Issue: 1, Pages: 111-119
Abstract
A multigenic family of selfglycosylating proteins named reversibly glycosylated polypeptides designated as RGPs have been usually associated with carbohydrate metabolism although they are an enigma both at the functional as well as at the structural level In this work we used biochemical approaches to demonstrate that complex formation is linked to rice plant development in which class 1 Oryza sativa RGP OsRGP would be involved in an early stage of growing plants while class 2 OsRGP would be associated with a late stage linked to an active polysaccharide synthesis that occurs during the elongation of plant Here a further investigation of the complex formation of the Solanum tuberosum RGP StRGP was performed Results showed that disulfide bonds are at least partially responsible for maintaining the oligomeric protein structure so that the nonreduced StRGP protein showed an apparent higher molecular weight and a lower radioglycosylation of the monomer with respect to its reduced form Hydrophobic cluster analysis and secondary structure prediction revealed that class 2 RGPs no longer maintained the Rossman fold described for class 1 RGP A 3D structure of the StRGP protein resolved by homology modeling supports the possibility of intercatenary disulfide bridges formed by exposed cysteines residues C79 C303 and C251 and they are most probably involved in complex formation occurring into the cell cytoplasmWe would like to thank the National Council for Scientific and Technological Research CONICET S Moreno is the career investigator of the CONICET V De Pino Fellowship CONICET Argentina 2005–2010 We also thank Susana Raffo and Marta L Bravo for excellent technical assistance
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