title: Characterization of a cold-adapted and salt-tolerant exo-chitinase (ChiC) from Pseudoalteromonas sp. DL-6.
abstract: We have previously reported a non-processive endo-type chitinase, ChiA, from a newly isolated marine psychrophilic bacterium, Pseudoalteromonas sp. DL-6. In this study, a processive exo-type chitinase, ChiC, was cloned from the same bacterium and characterized in detail. ChiC could hydrolyze crystalline chitin into (GlcNAc)2 as the only observed product. It exhibited high catalytic activity even at low temperatures, e.g. close to 0 °C, or in the presence of 5 M NaCl, suggesting that ChiC was a cold-adapted and highly salt-tolerant chitinase. ChiC could also hydrolyze other substrates, including chitosan and Avicel, indicating its broad substrate specificity. Sequence features indicated that ChiC was a multi-domain protein having a deep substrate-binding groove that was regarded as characteristic of processive exo-chitinases. Enzymatic hydrolysis of chitin by ChiC could be remarkably boosted in the presence of ChiA, suggesting the synergy of ChiC and ChiA. This work provided a new evidence to prove that marine psychrophilic bacteria utilized a synergistic enzyme system to degrade recalcitrant chitin.
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, People's Republic of China.|Natural Products and Glyco-Biotechnology Research Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, People's Republic of China.|School of Life Science and Biotechnology, Dalian University, Dalian, 116622, People's Republic of China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Life Science and Biotechnology, Dalian University, Dalian, 116622, People's Republic of China.
authors.forename: Naiyu
authors.initials: N
authors.lastname: Chi
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, People's Republic of China.
authors.forename: Fengwu
authors.initials: F
authors.lastname: Bai
authors.affiliation: Institute of Process Engineering, Chinese Academy of Science, Beijing, 100190, People's Republic of China.
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Du
authors.affiliation: Natural Products and Glyco-Biotechnology Research Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, People's Republic of China. zy1805@dicp.ac.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Natural Products and Glyco-Biotechnology Research Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, People's Republic of China. yinheng@dicp.ac.cn.
authors.forename: Heng
authors.initials: H
authors.lastname: Yin
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D006596:Hexosaminidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D031161:Pseudoalteromonas / Q000201:enzymology* / Q000235:genetics; D055049:Salt Tolerance
chemical_list: D001426:Bacterial Proteins; C079639:1,4-beta-chitobiosidase; D006596:Hexosaminidases
keywords: Chitin; Cold-adapted; Exochitinase; Pseudoalteromonas sp.; Salt-tolerant