Random sequence analysis of the genomic DNA of Methanopyrus kandleri and molecular cloning of the gene encoding a homologue of the catalytic subunit of carbon monoxide dehydrogenase

Abstract

Methanopyrus kandleri is a hyperthermophilic methanogen that represents one of the most heat-resistant organisms: the maximum growth temperature of M. kandleri is 110 degrees C. A random sequence analysis of the genomic DNA of M. kandleri has been performed to obtain genomic information. More than 200 unique sequence tags were obtained and compared with the sequences in the GenBank and PIR databases. About 30% of the analyzed tags showed strong sequence similarity to previously identified genes involved in various cellular processes such as biosynthesis, transport, methanogenesis, or metabolism. When statistics relating to the frequency of codons were examined, the sequenced open reading frames showed highly biased codon usage and a high content of charged amino acids. Among the identified genes, a homologue of the catalytic subunit of carbon monoxide dehydrogenase (CODH) that reduces CO2 to CO was cloned and sequenced in order to examine its detailed gene structure. The cloned gene includes consensus promoters. The amino acid sequence of the cloned gene shows a strong homology with the CODH genes from methanogenic Archaea, especially in the presumed binding sites for Fe-S centers.