IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Molecular characterization of chloroplastic Hsp100 chaperones from Arabidopsis thaliana.
Autor/es:
ROSANO, G. L.; CECCARELLI, E. A.
Lugar:
Mar del Plata, Buenos Aires
Reunión:
Congreso; XLIII Reunión Anual de la Sociedad Argentina de investigación en Bioquímica y Biología Molecular (SAIB); 2007
Institución organizadora:
Sociedad Argentina de investigación en Bioquímica y Biología Molecular
Resumen:
Molecular chaperones of the Hsp100 family have been identified inchloroplasts of , namely ClpC1, ClpC2 andClpD. By the use of knockout plants, it has been proposed that theseproteins may have multiple roles such as protein folding assistance,protein disaggregation, proteolysis and precursor import intochloroplasts. The study of these activities is still in its infancy due tothe fact that, to date, none of the chaperones have been purified. Themain goals of this work were to purify them using a bacterialexpression system and study their function . The cDNAswere obtained from the RIKEN cDNA bank, amplifiedby PCR and cloned into the vector pET28a. ClpC2 and ClpD wereexpressed and purified by affinity chromatography. They wererecovered as properly folded dimers with expected molecularweight. The proteins have basal Mg -dependent ATPase activity.While both proteins have similar Km values, the Vmax value ofClpD was almost two-fold higher than that of ClpC2. The influenceof temperature, pH, ionic strength and divalent cations was alsoassessed. Interestingly, ClpC2 was found to be the most heat stablemember of the Clp family with a temperature optimum of 55ºC. Bycontrast, ClpC1 could not be purified since its expression causesgrowth retardation and death to the host as judged by growth curvesand viable cell counts.