Biochemical properties and regulated gene expression of the superoxide dismutase from the facultatively aerobic hyperthermophile Pyrobaculum calidifontis.

ABSTRACT: Superoxide dismutase (SOD) was purified from a facultatively aerobic hyperthermophilic archaeon, Pyrobaculum calidifontis VA1. The purified native protein from aerobically grown cells exhibited 1,960 U of SOD activity/mg and contained 0.86 +/- 0.04 manganese and <0.01 iron atoms per subunit. The gene encoding SOD was cloned and expressed in Escherichia coli. Although the recombinant protein was soluble, little activity was observed due to the lack of metal incorporation. Reconstitution of the enzyme by heat treatment with either Mn or Fe yielded a highly active protein with specific activities of 1,970 and 434 U/mg, respectively. This indicated that the SOD from P. calidifontis was a cambialistic SOD with a preference toward Mn in terms of activity. Interestingly, reconstitution experiment

SUBMITTER: Amo T 

PROVIDER: S-EPMC219395 | biostudies-literature | 2003 Nov

REPOSITORIES: biostudies-literature