title: Structural basis for Fe-S cluster assembly and tRNA thiolation mediated by IscS protein-protein interactions.
abstract: The cysteine desulfurase IscS is a highly conserved master enzyme initiating sulfur transfer via persulfide to a range of acceptor proteins involved in Fe-S cluster assembly, tRNA modifications, and sulfur-containing cofactor biosynthesis. Several IscS-interacting partners including IscU, a scaffold for Fe-S cluster assembly; TusA, the first member of a sulfur relay leading to sulfur incorporation into the wobble uridine of several tRNAs; ThiI, involved in tRNA modification and thiamine biosynthesis; and rhodanese RhdA are sulfur acceptors. Other proteins, such as CyaY/frataxin and IscX, also bind to IscS, but their functional roles are not directly related to sulfur transfer. We have determined the crystal structures of IscS-IscU and IscS-TusA complexes providing the first insight into their different modes of binding and the mechanism of sulfur transfer. Exhaustive mutational analysis of the IscS surface allowed us to map the binding sites of various partner proteins and to determine the functional and biochemical role of selected IscS and TusA residues. IscS interacts with its partners through an extensive surface area centered on the active site Cys328. The structures indicate that the acceptor proteins approach Cys328 from different directions and suggest that the conformational plasticity of a long loop containing this cysteine is essential for the ability of IscS to transfer sulfur to multiple acceptor proteins. The sulfur acceptors can only bind to IscS one at a time, while frataxin and IscX can form a ternary complex with IscU and IscS. Our data support the role of frataxin as an iron donor for IscU to form the Fe-S clusters.
authors.affiliation: Department of Biochemistry, McGill University, Montréal, Québec, Canada.
authors.forename: Rong
authors.initials: R
authors.lastname: Shi
authors.forename: Ariane
authors.initials: A
authors.lastname: Proteau
authors.forename: Magda
authors.initials: M
authors.lastname: Villarroya
authors.forename: Ismaïl
authors.initials: I
authors.lastname: Moukadiri
authors.forename: Linhua
authors.initials: L
authors.lastname: Zhang
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Trempe
authors.forename: Allan
authors.initials: A
authors.lastname: Matte
authors.forename: M Eugenia
authors.initials: ME
authors.lastname: Armengod
authors.forename: Miroslaw
authors.initials: M
authors.lastname: Cygler
mesh_terms: D013437:Carbon-Sulfur Lyases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D012343:RNA, Transfer / Q000737:chemistry* / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D007506:Iron-Sulfur Proteins; C411665:IscU protein, E coli; D013438:Sulfhydryl Compounds; C551794:TusA protein, E coli; D013455:Sulfur; D012343:RNA, Transfer; D013437:Carbon-Sulfur Lyases; C080546:cysteine desulfurase
references.citation: Nat Struct Mol Biol. 2009 Apr;16(4):390-6
references.pmid: 19305405
references.citation: Structure. 2006 May;14(5):857-67
references.pmid: 16698547
references.citation: Methods Enzymol. 1997;276:307-26
references.pmid: 27754618
references.citation: Proc Natl Acad Sci U S A. 2000 Aug 1;97(16):8932-7
references.pmid: 10908679
references.citation: J Mol Biol. 2004 Nov 19;344(2):567-83
references.pmid: 15522305
references.citation: Proteins. 2005 Aug 15;60(3):566-9
references.pmid: 15937904
references.citation: J Biochem. 2002 May;131(5):679-85
references.pmid: 11983074
references.citation: Acta Crystallogr D Biol Crystallogr. 2004 Mar;60(Pt 3):432-8
references.pmid: 14993666
references.citation: J Bacteriol. 2002 Dec;184(24):6830-5
references.pmid: 12446633
references.citation: Structure. 2004 Nov;12(11):2037-48
references.pmid: 15530368
references.citation: Proc Natl Acad Sci U S A. 2008 Jun 24;105(25):8591-6
references.pmid: 18562278
references.citation: J Biol Chem. 2004 May 7;279(19):19551-8
references.pmid: 14978044
references.citation: J Mol Biol. 2002 Feb 1;315(5):1199-208
references.pmid: 11827487
references.citation: J Biol Chem. 2005 Sep 2;280(35):30660-70
references.pmid: 15983041
references.citation: J Biol Chem. 2000 Mar 24;275(12):8283-6
references.pmid: 10722656
references.citation: Acta Crystallogr D Biol Crystallogr. 1997 May 1;53(Pt 3):240-55
references.pmid: 15299926
references.citation: J Chromatogr. 1989 Jun 2;471:3-36
references.pmid: 2670985
references.citation: J Biol Chem. 2000 Oct 6;275(40):30753-6
references.pmid: 10900192
references.citation: Biochemistry. 1999 Dec 14;38(50):16561-8
references.pmid: 10600118
references.citation: J Mol Biol. 2000 Nov 24;304(2):219-29
references.pmid: 11080457
references.citation: J Mol Biol. 2000 May 12;298(4):691-704
references.pmid: 10788330
references.citation: Nucleic Acids Res. 2005 Jul 1;33(Web Server issue):W299-302
references.pmid: 15980475
references.citation: J Mol Biol. 2004 Sep 24;342(4):1265-78
references.pmid: 15351650
references.citation: J Biol Chem. 2009 Aug 14;284(33):21971-21980
references.pmid: 19491103
references.citation: Proc Natl Acad Sci U S A. 1993 Apr 1;90(7):2754-8
references.pmid: 8464885
references.citation: Nature. 2001 Jan 25;409(6819):529-33
references.pmid: 11206551
references.citation: J Mol Biol. 2004 Aug 6;341(2):605-15
references.pmid: 15276847
references.citation: J Biol Chem. 2007 Mar 16;282(11):7997-8004
references.pmid: 17244611
references.citation: Nat Chem Biol. 2006 Apr;2(4):185-94
references.pmid: 16547481
references.citation: Chem Commun (Camb). 2006 Aug 7;(29):3104-6
references.pmid: 16855700
references.citation: Proc Natl Acad Sci U S A. 2000 Jun 6;97(12):6640-5
references.pmid: 10829079
references.citation: Microbiol Mol Biol Rev. 2008 Mar;72(1):110-25, table of contents
references.pmid: 18322036
references.citation: J Mol Biol. 2008 Oct 31;383(1):133-43
references.pmid: 18723024
references.citation: FEMS Microbiol Rev. 2006 Nov;30(6):825-40
references.pmid: 17064282
references.citation: Biochemistry. 1994 Apr 19;33(15):4714-20
references.pmid: 8161529
references.citation: J Biol Chem. 2010 Jan 22;285(4):2302-8
references.pmid: 19946146
references.citation: Biochemistry. 2000 Feb 15;39(6):1263-73
references.pmid: 10684605
references.citation: Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 1):2126-32
references.pmid: 15572765
references.citation: J Biol Chem. 2006 Jun 16;281(24):16256-63
references.pmid: 16603772
references.citation: J Biol Chem. 2001 Nov 30;276(48):44521-6
references.pmid: 11577100
references.citation: Proc Natl Acad Sci U S A. 2000 Jul 5;97(14):7790-5
references.pmid: 10869428
references.citation: Acta Crystallogr D Biol Crystallogr. 2010 Feb;66(Pt 2):213-21
references.pmid: 20124702
references.citation: Proc Natl Acad Sci U S A. 2002 Apr 30;99(9):5948-52
references.pmid: 11972033
references.citation: Annu Rev Biochem. 2005;74:247-81
references.pmid: 15952888
references.citation: J Mol Biol. 2003 Jul 25;330(5):1049-59
references.pmid: 12860127
references.citation: Mol Cell. 2006 Jan 6;21(1):97-108
references.pmid: 16387657
references.citation: Biochemistry. 2004 Sep 28;43(38):12210-9
references.pmid: 15379559
references.citation: J Bacteriol. 2004 Feb;186(3):750-7
references.pmid: 14729701
references.citation: Biochemistry. 2008 Apr 1;47(13):3973-81
references.pmid: 18314963
references.citation: J Bacteriol. 2004 Feb;186(3):758-66
references.pmid: 14729702
references.citation: J Biol Chem. 1999 May 21;274(21):14768-72
references.pmid: 10329673
references.citation: J Biochem. 2002 May;131(5):713-9
references.pmid: 11983079
references.citation: J Mol Biol. 2006 Feb 10;356(1):97-110
references.pmid: 16343540
references.citation: J Mol Biol. 1968 Apr 28;33(2):491-7
references.pmid: 5700707
references.citation: Biochemistry. 2000 Jul 11;39(27):7856-62
references.pmid: 10891064
references.citation: FEBS Lett. 2005 Dec 19;579(30):6786-90
references.pmid: 16310786
references.citation: Structure. 2000 Jul 15;8(7):695-707
references.pmid: 10903947
references.citation: J Biol Chem. 2001 Sep 7;276(36):33588-95
references.pmid: 11443125
references.citation: FEBS Lett. 2005 Sep 26;579(23):5236-40
references.pmid: 16165131
references.citation: J Biol Chem. 2002 Apr 19;277(16):13367-70
references.pmid: 11882645
references.citation: Biochemistry. 2009 Jul 7;48(26):6062-71
references.pmid: 19492851
references.citation: J Biol Chem. 1998 May 22;273(21):13264-72
references.pmid: 9582371
references.citation: Arch Biochem Biophys. 2008 Jun 15;474(2):226-37
references.pmid: 18191630
references.citation: J Bacteriol. 2006 Apr;188(8):3052-62
references.pmid: 16585765