Affiliation:
1. Lehrstuhl für Technische Mikrobiologie, Universität Dortmund,1 and
2. Max-Delbrück-Centrum für Molekulare Medizin, D-13122 Berlin,2 Germany
3. Max-Planck-Institut für Molekulare Physiologie,3 D-44227 Dortmund, and
Abstract
ABSTRACT
The gene region coding for lithotrophic sulfur oxidation of
Paracoccus pantotrophus
GB17 is located on a 13-kb insert of plasmid pEG12. Upstream of the previously described six open reading frames (ORFs)
soxABCDEF
with a partial sequence of
soxA
and
soxF
(C. Wodara, F. Bardischewsky, and C. G. Friedrich, J. Bacteriol. 179:5014–5023, 1997), 4,350 bp were sequenced. The sequence completed
soxA
, and uncovered six new ORFs upstream of
soxA
, designated ORF1, ORF2, and ORF3, and
soxXYZ
. ORF1 could encode a 275-amino-acid polypeptide of 29,332 Da with a 61 to 63% similarity to LysR transcriptional regulators. ORF2 could encode a 245-amino-acid polypeptide of 26,022 Da with the potential to form six transmembrane helices and with a 48 to 51% similarity to proteins involved in redox transport in cytochrome
c
biogenesis. ORF3 could encode a periplasmic polypeptide of 186 amino acids of 20,638 Da with a similarity to thioredoxin-like proteins and with a putative signal peptide of 21 amino acids. Purified SoxXA, SoxYZ, and SoxB are essential for thiosulfate or sulfite-dependent cytochrome
c
reduction in vitro. N-terminal and internal amino acid sequences identified SoxX, SoxY, SoxZ, and SoxA to be coded by the respective genes. The molecular masses of the mature proteins determined by electrospray ionization spectroscopy (SoxX, 14,834 Da; SoxY, 11,094 Da; SoxZ, 11,717 Da; and SoxA, 30,452 Da) were identical or close to those deduced from the nucleotide sequence with differences for the covalent heme moieties. SoxXA represents a novel type of periplasmic
c
-type cytochromes, with SoxX as a monoheme and SoxA as a hybrid diheme cytochrome
c
. SoxYZ is an as-yet-unprecedented soluble protein. SoxY has a putative signal peptide with a twin arginine motif and possibly cotransports SoxZ to the periplasm. SoxYZ neither contains a metal nor a complex redox center, as proposed for proteins likely to be transported via the Tat system.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
136 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献