title: The crystal structure Escherichia coli Spy.
abstract: Escherichia coli spheroplast protein y (EcSpy) is a small periplasmic protein that is homologous with CpxP, an inhibitor of the extracytoplasmic stress response. Stress conditions such as spheroplast formation induce the expression of Spy via the Cpx or the Bae two-component systems in E. coli, though the function of Spy is unknown. Here, we report the crystal structure of EcSpy, which reveals a long kinked hairpin-like structure of four α-helices that form an antiparallel dimer. The dimer contains a curved oval shape with a highly positively charged concave surface that may function as a ligand binding site. Sequence analysis reveals that Spy is highly conserved over the Enterobacteriaceae family. Notably, three conserved regions that contain identical residues and two LTxxQ motifs are placed at the horizontal end of the dimer structure, stabilizing the overall fold. CpxP also contains the conserved sequence motifs and has a predicted secondary structure similar to Spy, suggesting that Spy and CpxP likely share the same fold.
authors.affiliation: Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea.
authors.forename: Eunju
authors.initials: E
authors.lastname: Kwon
authors.forename: Dong Young
authors.initials: DY
authors.lastname: Kim
authors.forename: Carol A
authors.initials: CA
authors.lastname: Gross
authors.forename: John D
authors.initials: JD
authors.lastname: Gross
authors.forename: Kyeong Kyu
authors.initials: KK
authors.lastname: Kim
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008968:Molecular Conformation; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D033903:Periplasmic Proteins / Q000737:chemistry* / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D029968:Escherichia coli Proteins; D033903:Periplasmic Proteins; C104888:Spy protein, E coli
references.citation: Nat Rev Microbiol. 2006 May;4(5):383-94
references.pmid: 16715050
references.citation: PLoS Genet. 2009 Sep;5(9):e1000651
references.pmid: 19763168
references.citation: Methods Enzymol. 1997;276:307-26
references.pmid: 27754618
references.citation: Bioinformatics. 2008 Dec 1;24(23):2780-1
references.pmid: 18818215
references.citation: Acta Crystallogr D Biol Crystallogr. 2003 Jul;59(Pt 7):1131-7
references.pmid: 12832755
references.citation: Curr Protoc Bioinformatics. 2002 Aug;Chapter 2:Unit 2.3
references.pmid: 18792934
references.citation: Acta Crystallogr D Biol Crystallogr. 1999 Apr;55(Pt 4):849-61
references.pmid: 10089316
references.citation: Mol Microbiol. 2000 Sep;37(5):1186-97
references.pmid: 10972835
references.citation: Arch Microbiol. 2000 Jan;173(1):78-82
references.pmid: 10648109
references.citation: Mol Microbiol. 2005 Apr;56(1):215-27
references.pmid: 15773991
references.citation: Proc Natl Acad Sci U S A. 2005 Dec 6;102(49):17775-9
references.pmid: 16303867
references.citation: J Bacteriol. 2005 Oct;187(19):6622-30
references.pmid: 16166523
references.citation: Bioinformatics. 2000 Apr;16(4):404-5
references.pmid: 10869041
references.citation: Nature. 2001 May 10;411(6834):215-9
references.pmid: 11346801
references.citation: Acta Crystallogr D Biol Crystallogr. 1997 May 1;53(Pt 3):240-55
references.pmid: 15299926
references.citation: Nucleic Acids Res. 2004 Jul 1;32(Web Server issue):W665-7
references.pmid: 15215472
references.citation: Acta Crystallogr D Biol Crystallogr. 1998 Sep 1;54(Pt 5):905-21
references.pmid: 9757107
references.citation: Nat Chem Biol. 2007 Jan;3(1):60-8
references.pmid: 17143269
references.citation: Curr Opin Microbiol. 2005 Apr;8(2):122-6
references.pmid: 15802241
references.citation: Protein J. 2007 Dec;26(8):556-61
references.pmid: 17805951
references.citation: J Biotechnol. 2008 Jan 20;133(2):196-200
references.pmid: 17884222
references.citation: Proc Natl Acad Sci U S A. 2001 Aug 28;98(18):10037-41
references.pmid: 11517324
references.citation: Nucleic Acids Res. 2008 Jan;36(Database issue):D281-8
references.pmid: 18039703
references.citation: J Bacteriol. 1999 Sep;181(17):5263-72
references.pmid: 10464196
references.citation: Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 1):2126-32
references.pmid: 15572765
references.citation: Acta Crystallogr D Biol Crystallogr. 2003 Jan;59(Pt 1):38-44
references.pmid: 12499537
references.citation: Annu Rev Microbiol. 2001;55:591-624
references.pmid: 11544368
references.citation: Adv Biochem Eng Biotechnol. 2004;89:1-45
references.pmid: 15217154
references.citation: J Appl Crystallogr. 2007 Aug 1;40(Pt 4):658-674
references.pmid: 19461840
references.citation: Appl Environ Microbiol. 2008 Jan;74(2):535-9
references.pmid: 18039828
references.citation: J Bacteriol. 1997 Mar;179(6):2073-6
references.pmid: 9068658
references.citation: Res Microbiol. 2006 May;157(4):306-14
references.pmid: 16487683