No abstract

Methane monooxygenase (MMO) is the enzyme responsible for the conversion of methane to methanol in methanotrophic bacteria. In addition, this enzyme complex oxidizes a wide range of aliphatic and aromatic compounds in a number of potentially useful biotransformations. In this study, we have used biochemical data obtained from purification and characterization of the soluble MMO from Methylococcus capsulatus (Bath), to identify structural genes encoding this enzyme by oligonucleotide probing. The genes encoding the beta and gamma subunits of MMO were found to be chromosomally located and were linked in this organism. We report here on the analysis of a recombinant plasmid containing 12 kilobases of Methylococcus DNA and provide the first evidence for the localization and linkage of genes encoding the methane monooxygenase enzyme complex. DNA sequence analysis suggests that the primary structures of the beta and gamma subunits of MMO are completely novel and the complete sequence of these genes is presented.

1. Summary A 5.8 kb fragment of chromosomal DNA from Methylococcus capsulatus (Bath) containing genes encoding the soluble methane monooxygenase enzyme complex was used as a probe for the detection of soluble monooxygenase genes in a number of representative strains of obligate methanotrophs. Only type II methanotrophs of the genus Methylosinus were found to contain homologues to the Methylococcus gene probe. This probe was also used successfully to detect soluble methane monooxygenase genes in a variety of methanotrophs by colony hybridizations.