CHROMOSOMAL ORGANIZATION AND NUCLEOTIDE-SEQUENCE OF THE FUS-GENE ENCODING ELONGATION-FACTOR-2 (EF-2) OF THE HYPERTHERMOPHILIC ARCHAEUM PYROCOCCUS-WOESEI

A Pyrococcus woesei EcoRI DNA fragment (3400 bp) harbouring the gene f us for elongation factor 2 (EF-2) was cloned and almost completely seq uenced. Unlike Methanococcus vannielii (which displays the 'str operon '-like fus and tuf gene context, 5'-rps12-rps7-fus-tuf-3'), and simila r to Sulfolobus acidocaldarius and Desulfurococcus mobilis, the Pyroco ccus fus gene (732 codons) is unlinked to the rps and tuf genes, and i s immediately followed (57 bp intergenic spacing) by an ORF of 106 cod ons. Both ORFs are preceded by potential archaeal promoters located 52 bp (for fus) and 37 bp (for ORF106) upstream of the putative start co dons. The Pyrococcus EF-2(G) equivalent factor is somewhat closer to t he eukaryal than to the bacterial homolog, and also shares with the fo rmer the C-terminal sequence required for ADP ribosylation of EF-2 by Diphtheria toxin.