title: Thermal stability and activity improvements of a Ca-independent α-amylase from Bacillus subtilis CN7 by C-terminal truncation and hexahistidine-tag fusion.
abstract: Simultaneous improvements of thermostability and activity of a Ca-independent α-amylase from Bacillus subtilis CN7 were achieved by C-terminal truncation and his₆-tag fusion. C-terminal truncation, which eliminates C-terminal 194-amino-acid residues from the intact mature α-amylase, raised the turnover number by 35% and increased the thermostability in terms of half-life at 65 °C by threefold. A his₆-tag fusion at either the C- or N-terminus of truncated α-amylase further enhanced its turnover number by 59% and 37%, respectively. Molecular modeling revealed that these improvements could be attributed to structural rearrangement and reorientation of the catalytic residues.
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing, People's Republic of China; State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Key Laboratory of Biorefinery, Guangxi Academy of Sciences, Nanning, People's Republic of China.
authors.forename: Chenghua
authors.initials: C
authors.lastname: Wang
authors.forename: Qingyan
authors.initials: Q
authors.lastname: Wang
authors.forename: Siming
authors.initials: S
authors.lastname: Liao
authors.forename: Bingfang
authors.initials: B
authors.lastname: He
authors.forename: Ribo
authors.initials: R
authors.lastname: Huang
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics; D020134:Catalytic Domain; D004795:Enzyme Stability; D006639:Histidine / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D000596:Amino Acids; C471213:His-His-His-His-His-His; D009842:Oligopeptides; D011993:Recombinant Fusion Proteins; D006639:Histidine; D000516:alpha-Amylases
keywords: Bacillus subtilis; hexahistidine tag; thermostability; truncation; α-amylase