Respiratory gene clusters of Metallosphaera sedula – differential expression and transcriptional organization

• DOI: 10.1099/mic.0.27515-0
• Publication Date: 2005-01-04T23:52:40Z
• Authors: Ulrike Kappler; Lindsay I. Sly; Alastair G. McEwan
• Keywords: Gene cluster

Metallosphaera sedula is a thermoacidophilic Crenarchaeon which capable of leaching metals from sulfidic ores. The authors have investigated the presence and expression genes encoding respiratory complexes in this organism when grown heterotrophically or chemolithotrophically on either sulfur pyrite. three gene clusters, two terminal oxidase complexes, quinol SoxABCD SoxM supercomplex, cluster high-potential cytochrome b components bc(1) complex analogue (cbsBA-soxL2N cluster) was established. Expression studies showed that soxM expressed to high levels during heterotrophic growth M. yeast extract, while soxABCD mRNA most abundant cells sulfur. Reduced-minus-oxidized difference spectra cell membranes cytochrome-related peaks correspond published Sulfolobus-type complexes. In pyrite-grown cells, monitored clusters were reduced by factor 10-12 relative maximal levels, although clearly contained oxidase-associated haems, suggesting additional oxidases sedula. Pyrite- sulfur-grown cbsA transcript, encodes membrane-bound with possible role iron oxidation chemolithotrophy. not co-transcribed soxL2N genes, therefore does appear be an integral part analogue. data show for first time differential response changing modes.