New Archaebacterial Genes Coding for Redox Proteins: Implications for the Evolution of Aerobic Metabolism

• DOI: 10.1006/jmbi.1995.0371
• Publication Date: 2002-10-07T16:32:07Z
• Authors: Jose Castresana; Mathias Lübben; Matti Saraste
• Keywords: Sulfolobus acidocaldarius; Copper protein

Archaebacterial respiratory chains are poorly understood at the molecular level. We have cloned and sequenced a cluster of five new genes from the archaebacterium Sulfolobus acidocaldarius, four of them coding for redox proteins: a Rieske iron-sulphur protein, a cytochrome b, a subunit II of cytochrome oxidase and a blue copper protein (sulfocyanin). The fifth gene codes for a hydrophobic protein with no homologue in the databases. The gene organization and biochemical data suggest that all four redox proteins probably form part of a membrane respiratory complex together with SoxM, a previously characterized catalytic subunit of cytochrome oxidase. A phylogenetic analysis of the new protein sequences gives support to the view that an elaborate aerobic respiratory chain was already present in the last common ancestor of all living organisms.