The carbohydrate-binding module of Fragaria x ananassa expansin 2 (CBM-FaExp2) binds to cell wall polysaccharides and decreases cell wall enzyme activities "in vitro"..

NARDI CRISTINA F.; ESCUDERO CRISTIAN M.; VILLARREAL N.; MARTÍNEZ GUSTAVO A.; CIVELLO P.

JOURNAL OF PLANT RESEARCH

SPRINGER TOKYO

Lugar: Tokyo; Año: 2013 vol. 126 p. 151 - 159

0918-9440

Abstract A putative carbohydrate binding module(CBM) from strawberry (Fragaria 9 ananassa Duch.)expansin 2 (CBM-FaExp2) was cloned and the encodingprotein was over-expressed in Escherichia coli and purifiedin order to evaluate its capacity to bind different cell wallpolysaccharides ??in vitro??. The protein CBM-FaExp2bound to microcrystalline cellulose, xylan and pectin withdifferent affinities (Kad = 33.6 ± 0.44 mL g-1, Kad =11.37 ± 0.87 mL g-1, Kad = 10.4 ± 0.19 mL g-1, respectively). According to ??in vitro?? enzyme assays, thisCBM is able to decrease the activity of cell wall degradingenzymes such as polygalacturonase, endo-glucanase, pectinase and xylanase, probably because the binding of CBMFaExp2 to the different substrates interferes with enzymeactivity. The results suggest that expansins would bind notonly cellulose but also a wide range of cell wall polymers