Affiliation:
1. Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905
Abstract
ABSTRACT
The crenarchaeal order
Sulfolobales
collectively contain at least five major terminal oxidase complexes. Based on genome sequence information, all five complexes are found only in
Metallosphaera sedula
and
Sulfolobus tokodaii
, the two sequenced
Sulfolobales
capable of iron oxidization. While specific respiratory complexes in certain
Sulfolobales
have been characterized previously as proton pumps for maintaining intracellular pH and generating proton motive force, their contribution to sulfur and iron biooxidation has not been considered. For
M. sedula
growing in the presence of ferrous iron and reduced inorganic sulfur compounds (RISCs), global transcriptional analysis was used to track the response of specific genes associated with these complexes, as well as other known and putative respiratory electron transport chain elements. Open reading frames from all five terminal oxidase or
bc
1
-like complexes were stimulated on one or more conditions tested. Components of the
fox
(Msed0467 to Msed0489) and
soxNL
-
cbsABA
(Msed0500 to Msed0505) terminal/quinol oxidase clusters were triggered by ferrous iron, while the
soxABCDD
′ terminal oxidase cluster (Msed0285 to Msed0291) were induced by tetrathionate and S
0
. Chemolithotrophic electron transport elements, including a putative tetrathionate hydrolase (Msed0804), a novel polysulfide/sulfur/dimethyl sulfoxide reductase-like complex (Msed0812 to Msed0818), and a novel heterodisulfide reductase-like complex (Msed1542 to Msed1550), were also stimulated by RISCs. Furthermore, several hypothetical proteins were found to have strong responses to ferrous iron or RISCs, suggesting additional candidates in iron or sulfur oxidation-related pathways. From this analysis, a comprehensive model for electron transport in
M. sedula
could be proposed as the basis for examining specific details of iron and sulfur oxidation in this bioleaching archaeon.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
83 articles.
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