Structural and functional characterization of ScsC, a periplasmic thioredoxin-like protein from Salmonella enterica Serovar typhimurium

Shepherd, Mark, Heras, Begona, Achard, Maud E. S., King, Gordon J., Argente, M. Pilar, Kurth, Fabian, Taylor, Samantha L., Howard, Mark J., King, Nathan P., Schembri, Mark A. and McEwan, Alastair G. (2013) Structural and functional characterization of ScsC, a periplasmic thioredoxin-like protein from Salmonella enterica Serovar typhimurium. Antioxidants and Redox Signaling, 19 13: 1494-1506. doi:10.1089/ars.2012.4939


Author Shepherd, Mark
Heras, Begona
Achard, Maud E. S.
King, Gordon J.
Argente, M. Pilar
Kurth, Fabian
Taylor, Samantha L.
Howard, Mark J.
King, Nathan P.
Schembri, Mark A.
McEwan, Alastair G.
Title Structural and functional characterization of ScsC, a periplasmic thioredoxin-like protein from Salmonella enterica Serovar typhimurium
Formatted title
Structural and functional characterization of ScsC, a periplasmic thioredoxin-like protein from Salmonella enterica Serovar typhimurium
Journal name Antioxidants and Redox Signaling   Check publisher's open access policy
ISSN 1523-0864
1557-7716
Publication date 2013-11-01
Year available 2013
Sub-type Article (original research)
DOI 10.1089/ars.2012.4939
Open Access Status Not yet assessed
Volume 19
Issue 13
Start page 1494
End page 1506
Total pages 13
Place of publication New Rochelle, NY, United States
Publisher Mary Ann Liebert
Language eng
Abstract Aims: The prototypical protein disulfide bond (Dsb) formation and protein refolding pathways in the bacterial periplasm involving Dsb proteins have been most comprehensively defined in Escherichia coli. However, genomic analysis has revealed several distinct Dsb-like systems in bacteria, including the pathogen Salmonella enterica serovar Typhimurium. This includes the scsABCD locus, which encodes a system that has been shown via genetic analysis to confer copper tolerance, but whose biochemical properties at the protein level are not defined. The aim of this study was to provide functional insights into the soluble ScsC protein through structural, biochemical, and genetic analyses. Results: Here we describe the structural and biochemical characterization of ScsC, the soluble DsbA-like component of this system. Our crystal structure of ScsC reveals a similar overall fold to DsbA, although the topology of -sheets and -helices in the thioredoxin domains differ. The midpoint reduction potential of the CXXC active site in ScsC was determined to be -132mV versus normal hydrogen electrode. The reactive site cysteine has a low pK(a), typical of the nucleophilic cysteines found in DsbA-like proteins. Deletion of scsC from S. Typhimurium elicits sensitivity to copper (II) ions, suggesting a potential involvement for ScsC in disulfide folding under conditions of copper stress. Innovation and Conclusion: ScsC is a novel disulfide oxidoreductase involved in protection against copper ion toxicity. Antioxid. Redox Signal. 19, 1494-1506.
Formatted abstract
Aims: The prototypical protein disulfide bond (Dsb) formation and protein refolding pathways in the bacterial periplasm involving Dsb proteins have been most comprehensively defined in Escherichia coli. However, genomic analysis has revealed several distinct Dsb-like systems in bacteria, including the pathogen Salmonella enterica serovar Typhimurium. This includes the scsABCD locus, which encodes a system that has been shown via genetic analysis to confer copper tolerance, but whose biochemical properties at the protein level are not defined. The aim of this study was to provide functional insights into the soluble ScsC protein through structural, biochemical, and genetic analyses.

Results: Here we describe the structural and biochemical characterization of ScsC, the soluble DsbA-like component of this system. Our crystal structure of ScsC reveals a similar overall fold to DsbA, although the topology of β-sheets and α-helices in the thioredoxin domains differ. The midpoint reduction potential of the CXXC active site in ScsC was determined to be-132 mV versus normal hydrogen electrode. The reactive site cysteine has a low pKa, typical of the nucleophilic cysteines found in DsbA-like proteins. Deletion of scsC from S. Typhimurium elicits sensitivity to copper (II) ions, suggesting a potential involvement for ScsC in disulfide folding under conditions of copper stress.

Innovation and Conclusion: ScsC is a novel disulfide oxidoreductase involved in protection against copper ion toxicity.
Keyword Biochemistry & Molecular Biology
Endocrinology & Metabolism
Biochemistry & Molecular Biology
Endocrinology & Metabolism
BIOCHEMISTRY & MOLECULAR BIOLOGY
ENDOCRINOLOGY & METABOLISM
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DP1096395
FT100100662
091163/Z/10/Z
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Chemistry and Molecular Biosciences
Institute for Molecular Bioscience - Publications
 
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