Cloning and expression of a beta-xylosidase (FaXyl1) from Fragaria x ananassa

BUSTAMANTE CA; PEDRO MARCOS CIVELLO; MARTÍNEZ GA

Pinamar, Pcia. Bueos Aires

Congreso; 10th Congress of PABMB (Panamerican Association for Biochemistry and Molecular Biology); 2005

PABMB y 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 B-xylosidase (FaXyll) from Fragaria X ananassa. The analysis of the predicted protein showed that FaXyll is closely related to other B-xylosidases from higher plants. Product of FaXyll 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 B-xylosidase activity against the artificial substrate p-nitrophenyl B-D-xilopyranoside. As other B-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 FaXyl 1 protein accumulation during ripening. A possible COOH-terminal processing of the primary translation product is discussed.