CLONING AND EXPRESSION OF A b-XYLOSIDASE (FaXyl1) FROM FRAGARIA X ANANASSA

BUSTMANTE CLAUDIA; CIVELLO PEDRO; MARTINEZ GUSTAVO

Pinamar, Argentina

Congreso; XLI Reunión Anual de SAIB (Sociedad Argentina de Investigación en Bioquímica y Biología Molecular); 2005

SAIB

Strawberry is a non-climateric fleshy fruit, which softens quickly and has short post-harvest life. The process is associated with an increment of pectin solubility and a reduction of the content of hemicelluloses. In this work, we cloned the full-lenght cDNA encoding a putative â-xylosidase (FaXyl1) from Fragaria X ananassa. The analysis of the predicted protein showed that FaXyl1 is closely related to other â-xylosidases from higher plants. Product of FaXyl1 contains a predicted signal peptide and seems to be targeted to the extracellular matrix. The presence of several potential N-glycosylation sites in the amino acid sequence is in accordance with the extracellular location. Recombinant protein over-expressed in E. coli showed â-xylosidase activity against the artificial substrate p-nitrophenyl â-D-xilopyranoside. As other â-xylosidases, the enzyme obtained from strawberry, showed a relatively high thermal stability. Western blot analysis of the corresponding protein was performed in strawberry cultivars with different softening rates. Softest cultivar showed a higher FaXyl1 protein accumulation during ripening. A possible COOH-terminal processing of the primary translation product is discussed