[Cloning and expression of a thermostable beta-glycosidase gene from Thermus nonproteolyticus HG102].
The gene coding for beta-glycosidase (EC3.2.1.21) from Thermus nonproteolyticus HG102 has been cloned and expressed in E. coli. The gene open reading frame was 1311 bp and it codes for 436 amino acids. The deduced amino acid sequence of the enzyme showed identity with members of glycosyl hydrolase family I. The enzyme had high content of hydrophobic amino acid (Ala 12.8%, Leu 10.9%), Arg(9.6%), Glu(9.4%) and Pro(8.0%), but low content Cys(0.45%) and Met (0.9%). From the alignment of enzyme amino acid sequence with other glycosyl hydrolase family I members, Glu164 and Glu338 were predicated as the proton donor and nucleophile group. The DNASTAR program was used to predict the secondary structure. According to the Chou-Fasman model, the enzyme has 41.4% of alpha-helics, 16.2%, beta-strands, 14.4%, beta-turns. 14 of the 35 Pro were located at the second sites of beta-turns. Hydrophobic interaction, ion bond, alpha-helics and Pro had important contribution to Tn-gly thermostability.
He
Xiang-Yuan
XY
Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China.
Jin
Cheng
C
Zhang
Shu-Zheng
SZ
Yang
Shou-Jun
SJ
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D006026:Glycoside Hydrolases / Q000096:biosynthesis* / Q000145:classification / Q000235:genetics; D006358:Hot Temperature; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D017433:Protein Structure, Secondary / Q000502:physiology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000379:methods; D017385:Sequence Homology; D013824:Thermus / Q000201:enzymology*; D001617:beta-Glucosidase
D011994:Recombinant Proteins; D006026:Glycoside Hydrolases; D001617:beta-Glucosidase; C441633:beta-glycosidase, Thermus nonproteolyticus