Abstract

A thermophilic new strain of Methanothermobacter marburgensis DX01, with a different morphology from M. thermautotrophicus delta H, was isolated from a hot spring in China. To provide further molecular evidence to identify the methanogen M. marburgensis DX01, polymerase chain reaction melting profile (PCR MP) technique and protein fingerprint profiling were performed. Both DNA and protein fingerprint profiles showed significant differences between M. marburgensis DX01 and M. thermautotrophicus delta H. In addition, five interesting DNA fragments obtained from PCR MP of the DX01 strain were excised and sequenced. We found that all five DNA fragments were unique to M. marburgensis DX01. Expression of induced proteins in M. marburgensis DX01 was analyzed by protein fingerprint profiling and a protein that was more highly expressed at 70°C was excised and identified by N-terminal amino acid sequencing. We found that the up-regulated protein was Methyl-coenzyme M reductase І, which was 97.6% amino acid sequence identity with that of M. thermautotrophicus delta H. These studies may provide clues for a better understanding of the new isolate of thermophilic M. marburgensis.

Key words: Methanothermobacter, polymerase chain reaction (PCR) melting profile, protein fingerprint profile analyses.