title: Structural and functional characterization of ScsC, a periplasmic thioredoxin-like protein from Salmonella enterica serovar Typhimurium.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  ScsC is a novel disulfide oxidoreductase involved in protection against copper ion toxicity.
authors: 1 School of Biosciences, University of Kent , Canterbury, United Kingdom .
authors: Mark
authors: M
authors: Shepherd
authors: Begoña
authors: B
authors: Heras
authors: Maud E S
authors: ME
authors: Achard
authors: Gordon J
authors: GJ
authors: King
authors: M Pilar
authors: MP
authors: Argente
authors: Fabian
authors: F
authors: Kurth
authors: Samantha L
authors: SL
authors: Taylor
authors: Mark J
authors: MJ
authors: Howard
authors: Nathan P
authors: NP
authors: King
authors: Mark A
authors: MA
authors: Schembri
authors: Alastair G
authors: AG
authors: McEwan
mesh_terms: D020134:Catalytic Domain; D003300:Copper / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D010084:Oxidation-Reduction; D033903:Periplasmic Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D012486:Salmonella typhimurium / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D013879:Thioredoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D033903:Periplasmic Proteins; D013879:Thioredoxins; D003300:Copper
references: J Biol Chem. 2009 Apr 10;284(15):10150-9
references: 19181668
references: Biochemistry. 1995 Apr 18;34(15):5075-89
references: 7536035
references: Gene. 2003 Jun 5;311:153-63
references: 12853150
references: Biochemistry. 2006 Dec 19;45(50):15100-10
references: 17154548
references: Protein Sci. 1998 Oct;7(10):2065-80
references: 9792093
references: J Mol Biol. 2009 Feb 13;386(1):60-71
references: 19073194
references: J Mol Biol. 2008 Aug 29;381(2):487-507
references: 18599072
references: Nature. 1964 Jan 11;201:185
references: 14118271
references: Science. 2009 Nov 20;326(5956):1109-11
references: 19965429
references: Proteins. 2006 Aug 15;64(3):559-74
references: 16736488
references: J Bacteriol. 2009 Jun;191(12):3901-8
references: 19376849
references: Nat Struct Biol. 2000 Mar;7(3):196-9
references: 10700276
references: Nucleic Acids Res. 2010 Jul;38(Web Server issue):W545-9
references: 20457744
references: Biochem J. 1991 Apr 15;275 ( Pt 2):341-8
references: 2025221
references: Protein Sci. 1998 May;7(5):1233-44
references: 9605329
references: Proc Natl Acad Sci U S A. 2004 Jul 6;101(27):10018-23
references: 15220477
references: Anal Biochem. 2003 Jan 15;312(2):224-7
references: 12531209
references: J Mol Biol. 2008 Jul 18;380(4):667-80
references: 18565543
references: J Mol Biol. 2009 Oct 2;392(4):952-66
references: 19631659
references: Methods Enzymol. 1984;107:281-94
references: 6503714
references: FEBS Lett. 1999 Apr 23;449(2-3):196-200
references: 10338131
references: Nat Rev Microbiol. 2009 Mar;7(3):215-25
references: 19198617
references: J Biol Chem. 1991 May 25;266(15):9494-500
references: 2033048
references: Microbiology (Reading). 2004 Sep;150(Pt 9):2993-3000
references: 15347757
references: Acta Crystallogr D Biol Crystallogr. 2010 Jan;66(Pt 1):12-21
references: 20057044
references: Acta Crystallogr D Biol Crystallogr. 2002 Nov;58(Pt 11):1955-7
references: 12393928
references: J Biol Chem. 2010 Jun 11;285(24):18423-32
references: 20233716
references: Methods Enzymol. 1997;276:307-26
references: 27754618
references: Proc Natl Acad Sci U S A. 2004 Jun 15;101(24):8876-81
references: 15184683
references: Nature. 1993 Sep 30;365(6445):464-8
references: 8413591
references: EMBO J. 2002 Jun 3;21(11):2646-54
references: 12032077
references: Biochemistry. 1994 May 17;33(19):5974-83
references: 8180227
references: FEBS Lett. 1998 May 29;428(3):255-8
references: 9654144
references: Antioxid Redox Signal. 2009 Jul;11(7):1485-500
references: 19265485
references: Antioxid Redox Signal. 2011 Jul 1;15(1):49-66
references: 20849374
references: Chem Commun (Camb). 2013 Mar 4;49(18):1847-9
references: 23360928
references: Cell. 1999 Jul 23;98(2):217-27
references: 10428033
references: Proc Natl Acad Sci U S A. 2006 Apr 11;103(15):5977-82
references: 16585510
references: Can J Microbiol. 2001 Aug;47(8):711-21
references: 11575497
references: J Biol Chem. 2009 Aug 28;284(35):23719-33
references: 19535335
references: Biochemistry. 1996 Nov 19;35(46):14503-11
references: 8931546
references: Acta Crystallogr D Biol Crystallogr. 2010 Nov;66(Pt 11):1153-63
references: 21041930
references: Proc Natl Acad Sci U S A. 2000 Jun 6;97(12):6640-5
references: 10829079
references: Acta Crystallogr D Biol Crystallogr. 2008 Jan;64(Pt 1):125-32
references: 18094476
references: J Immunol. 2005 Feb 1;174(3):1491-500
references: 15661908
references: Gene. 1991 Apr;100:195-9
references: 2055470
references: J Bacteriol. 2003 Feb;185(3):991-1000
references: 12533475
references: Cell. 2006 Nov 17;127(4):789-801
references: 17110337
references: Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 1):2126-32
references: 15572765
references: Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 May 1;66(Pt 5):601-4
references: 20445269
references: J Biol Chem. 2006 Feb 24;281(8):4911-9
references: 16280324
references: Proc Natl Acad Sci U S A. 2008 Aug 19;105(33):11933-8
references: 18695247
references: J Bacteriol. 1997 Aug;179(16):4977-84
references: 9260936
references: Infect Immun. 2009 Nov;77(11):4934-9
references: 19687198
references: J Biol Chem. 2012 Apr 20;287(17):13549-55
references: 22389498
references: J Biol Chem. 2009 Jun 26;284(26):17835-45
references: 19389711
references: J Biol Chem. 1997 Dec 5;272(49):30780-6
references: 9388218
references: J Biol Chem. 2000 Jul 28;275(30):22743-9
references: 10930424
references: J Biol Chem. 1999 Mar 19;274(12):7784-92
references: 10075670
references: Protein Expr Purif. 2005 May;41(1):207-34
references: 15915565
references: mBio. 2012 Apr 03;3(2):
references: 22493033