The carbohydrate-binding module of Fragaria × ananassa expansin 2 (CBM-FaExp2) binds to cell wall polysaccharides and decreases cell wall enzyme activities “in vitro”
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A putative carbohydrate binding module (CBM) from strawberry (Fragaria × ananassa Duch.) expansin 2 (CBM-FaExp2) was cloned and the encoding protein was over-expressed in Escherichia coli and purified in order to evaluate its capacity to bind different cell wall polysaccharides “in vitro”. The protein CBM-FaExp2 bound to microcrystalline cellulose, xylan and pectin with different 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, this CBM is able to decrease the activity of cell wall degrading enzymes such as polygalacturonase, endo-glucanase, pectinase and xylanase, probably because the binding of CBM-FaExp2 to the different substrates interferes with enzyme activity. The results suggest that expansins would bind not only cellulose but also a wide range of cell wall polymers.
KeywordsCBM Cell wall Expansin Hydrolases Strawberry
This work has been supported by grants from CONICET (PIP 0062), ANPCYT (PICT 2006-01140) and UNSAM (Biotechnology Program 2007). Authors thank José Luis Burgos (Comisión de Investigaciones Científicas, CIC) for valuable technical assistance.
- Brummell DA, Lashbrook CC, Bennett AB (1994) Plant endo-1,4-β-d-glucanases. Structure, properties, and physiological function. Am Chem Soc Symp Ser 566:100–129Google Scholar
- Cleemput G, Hessing M, van Oort M, Deconynck M, Delcour JA (1997) Purification and characterization of a β-d-xylosidase and an endo-xylanase from wheat flour. Plant Physiol 11:377–386Google Scholar
- Gross KC (1982) A rapid and sensitive spectrophotometric method for assaying polygalacturonase using 2-cyanoacetamide. HortScience 17:933–934Google Scholar
- Hiwasa K, Nakano R, Hashimoto A, Matsuzaki M, Murayama H, Inaba A, Kub Y (2004) European, Chinese and Japanese pear fruits exhibit differential softening characteristics during ripening. J Exp Bot 27:1–10Google Scholar
- Obembe OO, Jacobsen E, Visser RGF, Vincken JP (2007a) Expression of an expansin carbohydrate-binding module affects xylem and phloem formation. Afr J Biotechnol 6:1608–1616Google Scholar
- Wong KKY, Tan LUL, Saddler JN (1998) Multiplicity of β-1,4-xylanase in microorganisms: functions and applications. Microbiol Rev 52:305–317Google Scholar
- Yoshida K, Imaizumi N, Kaneko S, Kawagoe Y, Tagiri A, Tanaka H, Nishitani K, Komae K (2006) Carbohydrate-binding module of a rice endo-β-1,4-glycanase, OsCel9A, expressed in auxin-induced lateral root primordia, is post-translationally truncated. Plant Cell Physiol 47:1555–1571PubMedCrossRefGoogle Scholar