Characterization of novel Ostreococcus tauri starch binding domains

HEDIN, N.; BARCHIESI, J.; GOMEZ-CASATI, D.F.; BUSI, M.V.

FLORIANÓPOLIS

Congreso; IV SOLABIAA LATIN AMERICAN CONGRESS; 2015

SOCIEDAD LATINOAMERICANA DE BIOTECNOLOGÍA AMBIENTAL Y ALGAL

    StarchBinding Domains (SBD) are one type of carbohydrate binding domains (CBM) thathave acquired the evolutionary advantage of being able to interact and disruptthe substrate surface on a particular way. This can be accomplished because thiskind of CBM presents two polysaccharide binding sites [1]. The proteinscontaining these CBMs show a strong physical association with the differentsubstrates, increasing the rate of enzymatic reactions. These modules occuralso in proteins with no hydrolytic activity, constituting a core from whichthe catalytic proteins are organized [2]. These properties make SBDs a verypowerful molecular tool, allowing to us the possibility to engineeringhydrolytic enzymes to increase its catalytic efficiencies when added in trans,and a powerful means of polysaccharide destructuration.    In thiswork, we analyze the SBDs present in two degradative enzymes involved in starchcatabolism in Ostreococcus tauri. One of these SBD belongs to the family CBM20according to the CAZY classification (http://www.cazy.org/fam/acc_CBM.html).This SBD is part of the glucan 1,4-α-glucosidase (EC 3.2.1.3, Ot06g02060) thatcatalyze the hydrolysis of terminal 1,4-α-D-glucose residues from non-reducingends. The second SBD belongs to the family CBM48 of the CAZY classification andis present in the glycogen 6-alpha-D-glucanohydrolase (EC 3.2.1.68, Ot14g02550)that catalyze the hydrolysis of 1,6-α-D-glucosidic bonds in branchedpolysaccharides.