Sequencing and expression of the gene encoding a cold-active citrate synthase from an Antarctic bacterium, strain DS2-3R.
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Gerike U, Danson MJ, Russell NJ, Hough DW
Sequencing and expression of the gene encoding a cold-active citrate synthase from an Antarctic bacterium, strain DS2-3R.
Eur J Biochem. 1997 Aug 15;248(1):49-57.
- PubMed ID
- 9310359 [ View in PubMed]
- Abstract
The gene encoding citrate synthase from a novel bacterial isolate (DS2-3R) from Antarctica has been cloned, sequenced and over expressed in Escherichia coli. Both the recombinant enzyme and the native enzyme, purified from DS2-3R, are cold-active, with a temperature optimum of 31 degrees C. In addition the enzymes are rapidly inactivated at 45 degrees C, and show significant activity at 10 degrees C and below. Comparison of amino acid sequences indicates that DS2-3R citrate synthase is most closely related to the enzyme from gram-positive bacteria. The amino acid sequence of the DS2-3R enzyme shows several features previously recognised in other cold-active enzymes, including an extended surface loop, an increase in the occurrence of charged residues and a decrease in the number of proline residues in loops. Other changes observed in some psychrophilic enzymes, such as a decrease in isoleucine content and in arginine/(arginine+lysine) content, were not seen in this case.