Ecology, biochemistry and genetics of methylotropic bacteria
Some bacteria that grow on methanol synthesize methanol dehydrogenase as 20% of the total cellular protein. This enzyme contains a large and small subunit. The structural genes for these subunits, for a chaperone and proteins required to attach the prosthetic group and incorporate calcium into the active site of the enzyme, are linked on the genome. Eight positively-acting regulatory proteins have been identified that are uniquely required for transcription of the genes in this regulon. Four are required for methanol dehyrogenase expression only and four others are required for expression of MDH as well as several other methanol inducible regulons. We are attempting to purify the regulatory proteins and identify their interactions and binding sites on DNA segments upstream of the MDH regulon.
We also study the ecology of very diverse bacteria that oxidize methane. We use phylogenetic signature probes and gene probes that encode unique enzymes in methane-oxidizing bacteria to detect these bacteria in complex communities of bacteria from natural habitats. We also use newly developed techniques to isolate new methane-oxidizing bacteria. These techniques include opposing gradients of gases and other chemicals that allow us to separate and grow different methanotrophs in agarose columns.
Publications
- Jahng D. , C.S. Kim, R.S. Hanson, and T.K. Wood. (1996) Optimization of trichloroethylene degredation using solumble methane monooxygenase of Methylosinus trichosporium OB3b expressed in recombinant bacteria. Biotechnology and Bioengineering 51:349-359.
- Hanson R.S. , and T.E. Hanson. (1996) Methanotrophic Bacteria. Microbiological Reviews 439-471.
- Xu, H., J. Janka, M. Viebahn, and R.S. Hanson. (1995) Nucleotide sequence of the mxcQ and mxcE genes required for methanol dehydrogenase synthese in Methylobacterium organophilum XX: A two-component regulatory system. Microbiology 141:2543-2251.
- Brusseau, G.A., E.S. Boulygina, and R.S. Hanson. (1994) Phylogenetic analysis and development of probes for differentiating methylotrophic bacteria. Appl. Environ. Microbiol. 60:626-636.
