Molecular cloning, expression, purification and characterization of thioredoxin from Antarctic sea-ice bacteria Pseudoalteromonas sp. AN178.
Thioredoxin (Trx) is a highly conserved and multi-functional protein that plays a pivotal role in maintaining the redox state of the cell and in protecting the cell against oxidative stress. Trx gene from Antarctic sea-ice bacteria Pseudoalteromonas sp. AN178 was cloned and expressed as soluble protein in Escherichia coli (designated as PsTrx). Trx gene consisted of an open reading frame of 324-bp nucleotides encoding a protein of 108 amino acids with a calculated molecular mass of 11.88 kDa. The deduced protein included the conserved Cys-Gly-Pro-Cys active-site sequence. After purification by a single step Ni-NTA affinity chromatography, recombinant PsTrx with a high specific activity of 96.67 U/mg was obtained. The purified PsTrx had an optimal temperature and pH of 25 °C and 7.0, respectively, and showed about 55 % of the residual catalytic activity even at 0-10 °C. It had high tolerance to a wide range of NaCl concentrations (0-2 M NaCl) and was stable in the presence of H2O2. This research suggested that PsTrx displayed unique catalytic properties.
School of Marine and Technology, Harbin Institute of Technology, Weihai, 264209, People's Republic of China.
Quanfu
Q
Wang
Yanhua
Y
Hou
Junjie
J
Qu
Yanyan
Y
Hong
Yifei
Y
Lin
Xiao
X
Han
D000595:Amino Acid Sequence; D000864:Antarctic Regions; D003001:Cloning, Molecular; D006863:Hydrogen-Ion Concentration; D046448:Ice Cover / Q000382:microbiology*; D008969:Molecular Sequence Data; D009792:Oceans and Seas; D055550:Protein Stability; D031161:Pseudoalteromonas / Q000235:genetics*; D011994:Recombinant Proteins / Q000302:isolation & purification; D016415:Sequence Alignment; D013696:Temperature; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*
D011994:Recombinant Proteins; D013879:Thioredoxins