title: Characterization of a lichenase isolated from soil metagenome.
abstract: A lichenase gene (mt-lic) was identified for the first time through function-based screening of a soil metagenomic library. Its deduced amino acid sequence exhibited a high degree of homology with endo-β-1,3-1,4-glucanase (having both lichenase and chitosanase activities), encoded by the bgc gene of Bacillus circulans WL-12. The recombinant lichenase overexpressed and purified from Escherichia coli was able to efficiently hydrolyze both barley β-glucan and lichenan. The enzyme showed maximal activity at a pH of 6.0 at 50°C, with Azo-barley-glucan as the substrate. The metal ions Mn(2+), Mg(2+), Ca(2+), and Fe(2+) enhanced the enzymatic activity, whereas the Cu(2+) and Zn(2+) ions inhibited the enzymatic activity. The Km and Vmax values of the purified lichenase were determined to be 0.45 mg/ml and 24.83 U/min/mg of protein, respectively.
authors.affiliation: Synthetic Biology and Bioengineering, Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Republic of Korea.
authors.forename: Sang-Yoon
authors.initials: SY
authors.lastname: Kim
authors.forename: Doo-Byoung
authors.initials: DB
authors.lastname: Oh
authors.forename: Ohsuk
authors.initials: O
authors.lastname: Kwon
mesh_terms: D001407:Bacillus / Q000235:genetics; D003001:Cloning, Molecular; D020536:Enzyme Activators / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D015723:Gene Library; D005936:Glucans / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D056186:Metagenomics; D008670:Metals / Q000378:metabolism; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012988:Soil Microbiology; D013379:Substrate Specificity; D013696:Temperature; D047071:beta-Glucans / Q000378:metabolism
chemical_list: D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D005936:Glucans; D008670:Metals; D011994:Recombinant Proteins; D047071:beta-Glucans; D006026:Glycoside Hydrolases; C028020:licheninase; C015968:lichenin