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Discovery of the catalytic function of a putative 2‐oxoacid dehydrogenase multienzyme complex in the thermophilic archaeon Thermoplasma acidophilum
Author(s) -
Heath Caroline,
Jeffries Alex C.,
Hough David W.,
Danson Michael J.
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.10.058
Subject(s) - thermoplasma acidophilum , thermophile , operon , archaea , biology , biochemistry , sulfolobus solfataricus , dehydrogenase , gene , tetramer , enzyme , escherichia coli
Those aerobic archaea whose genomes have been sequenced possess a single 4‐gene operon that, by sequence comparisons with Bacteria and Eukarya, appears to encode the three component enzymes of a 2‐oxoacid dehydrogenase multienzyme complex. However, no catalytic activity of any such complex has ever been detected in the Archaea. In the current paper, we have cloned and expressed the first two genes of this operon from the thermophilic archaeon, Thermoplasma acidophilum . We demonstrate that the protein products form an α 2 β 2 hetero‐tetramer possessing the decarboxylase catalytic activity characteristic of the first component enzyme of a branched‐chain 2‐oxoacid dehydrogenase multienzyme complex. This represents the first report of the catalytic function of these putative archaeal multienzyme complexes.