CEFOBI   05405
CENTRO DE ESTUDIOS FOTOSINTETICOS Y BIOQUIMICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Starch-binding domains conservation in starch synthase III isoforms.
Autor/es:
BARCHIESI, J.; HEDIN, N.; GOMEZ-CASATI, D.F; BUSI, M.V.
Lugar:
CABA, Buenos Aires
Reunión:
Congreso; Reunión Satélite de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2013
Institución organizadora:
SAIB
Resumen:
Starch-binding domains (SBDs) are key modules present in numerous polysaccharide metabolism enzymes. These modules are essential for starch-binding and catalytic activity of starch synthaseIII from A. thaliana. In Ostreococcus tauri, a unicellular green alga, there are three SSIII isoforms, known as Ostta SSIII-A, SSIII-B and SSIII-C. In silico studies show that these three isoforms containtwo, three and no N-terminal SBDs, respectively. In addition, phylogenetic analysis has indicated that OsttaSSIII-A N-terminal fragment is closely related to SSIII N-terminal sequences from othergreen microalgae. Besides, we observed variable SBDs sizes and numbers in green algae SSIII enzymes. Furthermore, sequence alignment and homology modeling data showed that 3-D structures obtained and the amino acid residues implicated in starch binding are well conserved in OsttaSSIII SBD, except in OsttaSSIII-B D1, which might possibly undergo a deletion in the n N-terminal region. Preliminary results from affinity gel electrophoresis assays suggest that OsttaSSIII SBDs displayed some promiscuity in the binding to different polysaccharide substrates. These results not only discloses significant information concerning evolutionary and structure?function aspects of SBD domains, but are also crucial to better understand the metabolism of starch in algae.