caa a22 4500 605500851 CHVBK 20210128100558.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00253-015-6746-3 doi (NATIONALLICENCE)springer-10.1007/s00253-015-6746-3 Expression and characteristics of a Ca2+-dependent endoglucanase from Cytophaga hutchinsonii [Elektronische Daten] [Cong Zhang, Weican Zhang, Xuemei Lu] Cytophaga hutchinsonii is a Gram-negative bacterium that can degrade crystalline cellulose efficiently with an unknown strategy. Genomic analysis suggested it lacks exoglucanases which are found in many cellulolytic organisms and most of the cellulases in C. hutchinsonii lack recognizable carbohydrate-binding modules (CBMs). CHU_1280, speculated to be an endoglucanase belonging to glycoside hydrolase family 9 (GH9) in C. hutchinsonii, was functionally expressed in Escherichia coli, and evidence was presented suggesting that it may be a processive endoglucanase. In the absence of Ca2+, CHU_1280 was inactive. But in the presence of Ca2+, it had a specific activity of 600U/μmol with carboxymethyl cellulose (CMC) as the substrate. With Ca2+, CHU_1280 hydrolyzed regenerated amorphous cellulose (RAC) with nearly 80% of the reducing ends appearing in the soluble fraction, suggesting it degraded cellulose in a processive way. CHU_1280 could bind to cellulose without recognizable CBMs and its binding ability was also Ca2+-dependent. Ca2+ could stabilize the catalytic domain at high temperature, but the denaturation temperature of the whole protein was decreased. C. hutchinsonii might have an exoglucanase-independent cellulases system which included endoglucanases, processive endoglucanases, and β-glucosidases. Springer-Verlag Berlin Heidelberg, 2015 Cytophaga hutchinsonii nationallicence Family 9 glycoside hydrolase nationallicence Endoglucanase nationallicence Calcium-dependent nationallicence Zhang Cong State Key Laboratory of Microbial Technology, College of Life Science, Shandong University, 250100, Jinan, China aut Zhang Weican State Key Laboratory of Microbial Technology, College of Life Science, Shandong University, 250100, Jinan, China aut Lu Xuemei State Key Laboratory of Microbial Technology, College of Life Science, Shandong University, 250100, Jinan, China aut Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/22(2015-11-01), 9617-9623 0175-7598 99:22<9617 2015 99 253 https://doi.org/10.1007/s00253-015-6746-3 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00253-015-6746-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhang Cong State Key Laboratory of Microbial Technology, College of Life Science, Shandong University, 250100, Jinan, China aut NATIONALLICENCE 700 1- Zhang Weican State Key Laboratory of Microbial Technology, College of Life Science, Shandong University, 250100, Jinan, China aut NATIONALLICENCE 700 1- Lu Xuemei State Key Laboratory of Microbial Technology, College of Life Science, Shandong University, 250100, Jinan, China aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/22(2015-11-01), 9617-9623 0175-7598 99:22<9617 2015 99 253