Hydrogen/sulfur metabolism in the hyperthermophilic archaebacterium Pyrodictium brockii. Progress report, March 1, 1989--February 28, 1990.

摘要

The mechanisms by which hyperthermophilic archaebacteria grow and carry out metabolic functions at elevated temperatures have yet to be determined. Progress along these lines requires some understanding of the roles that molecular hydrogen and elemental sulfur play in their metabolism. The objectives of the work proposed here include developing an understanding of the metabolic characteristics of, and the enzymes involved in, hydrogen/sulfur transformation by hyperthermophilic archaebacteria. Efforts will focus primarily on the autotrophic bacterium, Pyrodictium brockii, which has a reported optimum growth temperature (105(degree)C) in pure culture. Biochemical and genetic characterization of enzymes involved in hydrogen/sulfur transformations for these organisms will be pursued. These include the H(sub 2)-activating hydrogenase enzyme, a ubiquinone, a c-type cytochrome, and the S-reducing complex. Comparisons of the biochemical and genetic properties of these electron transport components will be made with mesophilic counterparts. Characterization of both purified hydrogenase and the cloned hydrogenase gene will receive a major research effort. The long-term goal is to understand the biochemical basis of extreme thermophily. (ERA citation 15:033211)