Brian P. Kaine

The complete 1.66-megabase pair genome sequence of an autotrophic archaeon, Methanococcus jannaschii, and its 58- and 16-kilobase pair extrachromosomal elements have been determined by whole-genome random sequencing. A total of 1738 predicted protein-coding genes were identified; however, only a minority of these (38 percent) could be assigned a putative cellular role with high confidence. Although the majority of genes related to energy production, cell division, and metabolism in M. jannaschii are most similar to those found in Bacteria, most of the genes involved in transcription, translation, and replication in M. jannaschii are more similar to those found in Eukaryotes.

Sequences of two putative tRNA genes, for serine and leucine, from the archaebacterium Sulfolobus solfataricus contain intervening sequences in the anticodon region. Furthermore, the genes lack encoded CCA 3' termini and are flanked by A + T-rich DNA segments. The introns can both form the same secondary structure, which is a double-helical extension of the anticodon stalk. The resulting structure contains two symmetrically placed 3-base bulge loops, in which are located cleavage sites for the introns. In the one case tested, the gene occurs as a single copy in the genome.

Nature 390, 364–370; (1997) The pathway for sulphate reduction is incorrect as published: in Fig. 3 on page 367, adenylyl sulphate 3-phosphotransferase (cysC) is not needed in the pathway as outlined, as adenylyl sulphate reductase (aprAB) catalyses the first step in the reduction of adenylyl sulphate.