title: Characterization and a point mutational approach of a psychrophilic lipase from an arctic bacterium, Bacillus pumilus.
abstract: A bacterium with lipolytic activity was isolated from the Chukchi Sea within the Arctic Ocean. The lipase BpL5 from the isolate, Bacillus pumilus ArcL5, belongs to subfamily 4 of lipase family I. The optimum pH and temperature of the recombinant enzyme BpL5, as expressed in Escherichia coli, were 9.0 and 20 °C, respectively. The enzyme retained 85 % of its activity at 5 °C. There was a significant difference between temperatures for maximal activity (20 °C) and for protein denaturation (approx. 45 °C). The enzyme preferred middle-chain (C8) p-nitrophenyl substrates. Two mutants, S139A and S139Y, were rationally designed based on the 3D-structure model, and their activities were compared with that of the wild type. The both mutants showed significantly improved activity against tricaprylin.
authors.affiliation: Division of Life Sciences, Korea Polar Research Institute (KOPRI), 26, Songdomirae-ro, Yeonsu-gu, Incheon, 406-840, Republic of Korea.
authors.forename: Ah Ram
authors.initials: AR
authors.lastname: Wi
authors.forename: Sung-Jong
authors.initials: SJ
authors.lastname: Jeon
authors.forename: Sunghui
authors.initials: S
authors.lastname: Kim
authors.forename: Ha Ju
authors.initials: HJ
authors.lastname: Park
authors.forename: Dockyu
authors.initials: D
authors.lastname: Kim
authors.forename: Se Jong
authors.initials: SJ
authors.lastname: Han
authors.forename: Joung Han
authors.initials: JH
authors.lastname: Yim
authors.forename: Han-Woo
authors.initials: HW
authors.lastname: Kim
mesh_terms: D019943:Amino Acid Substitution; D001110:Arctic Regions; D001407:Bacillus / Q000201:enzymology* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D009792:Oceans and Seas; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012623:Seawater / Q000382:microbiology; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D050505:Mutant Proteins; D011994:Recombinant Proteins; D008049:Lipase