FIG. 1.

The nucleotide sequence of a 1,119-bp StyI-PstI DNA fragment containing part of orfA and orfB and the complete hpt gene of M. thermoautotrophicum Marburg. The deduced amino acid sequence of the HGPRTase, encoded by hpt, and the two open reading frames are shown above the sequence. The amino acids shown in bold have been verified by N-terminal sequencing of the purified HGPRTase. The potential ribosome binding sites in front of the open reading frames are marked with #. Relevant restriction sites are indicated and double underlined. The transcriptional start sites of the hpt gene, as identified by primer extension (Fig. 2) are marked with arrows, and the putative promoter region is marked with asterisks. Amino acids encoded by infrequently used arginine and isoleucine codons in E. coli are boxed.