GENE CLONING AND EXPRESSION AND CHARACTERIZATION OF A TOXIN-SENSITIVEPROTEIN PHOSPHATASE FROM THE METHANOGENIC ARCHAEON METHANOSARCINA-THERMOPHILA-TM-1

With oligonucleotides modelled after conserved regions within the prot ein-serine/threonine phosphatases (PPs) of the PP1/2A/2B superfamily, the gene for the archaeal protein phosphatase PP1-arch2 was identified , cloned, and sequenced from the methanogenic archaeon Methanosarcina thermophila TM-1. The DNA-derived amino acid sequence of PP1-arch2 exh ibited a high degree of sequence identity, 27 to 31%, with members of the PP1/2A/2B superfamily such as PP1-arch1 from Sulfolobus solfataric us, PP1 alpha from rats, PP2A from Saccharomyces cerevisiae, and PP2B from humans, The activity of the recombinant PP1-arch2 Has sensitive t o several naturally occurring microbial toxins known to potently inhib it eucaryal PP1 and PP2A, including microcystin-LR, okadaic acid, taut omycin, and calyculin A.