title: His86 from the N-terminus of frataxin coordinates iron and is required for Fe-S cluster synthesis.
abstract: Human frataxin has a vital role in the biosynthesis of iron-sulfur (Fe-S) clusters in mitochondria, and its deficiency causes the neurodegenerative disease Friedreich's ataxia. Proposed functions for frataxin in the Fe-S pathway include iron donation to the Fe-S cluster machinery and regulation of cysteine desulfurase activity to control the rate of Fe-S production, although further molecular detail is required to distinguish these two possibilities. It is well established that frataxin can coordinate iron using glutamate and aspartate side chains on the protein surface; however, in this work we identify a new iron coordinating residue in the N-terminus of human frataxin using complementary spectroscopic and structural approaches. Further, we demonstrate that His86 in this N-terminal region is required for high affinity iron coordination and iron assembly of Fe-S clusters by ISCU as part of the Fe-S cluster biosynthetic complex. If a binding site that includes His86 is important for Fe-S cluster synthesis as part of its chaperone function, this raises the possibility that either iron binding at the acidic surface of frataxin may be spurious or that it is required for protein-protein interactions with the Fe-S biosynthetic quaternary complex. Our data suggest that iron coordination to frataxin may be significant to the Fe-S cluster biosynthesis pathway in mitochondria.
authors.affiliation: Department of Chemistry, The University of Alabama , Tuscaloosa, Alabama 35487-0336, United States.
authors.forename: Leslie E
authors.initials: LE
authors.lastname: Gentry
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Thacker
authors.forename: Reece
authors.initials: R
authors.lastname: Doughty
authors.forename: Russell
authors.initials: R
authors.lastname: Timkovich
authors.forename: Laura S
authors.initials: LS
authors.lastname: Busenlehner
mesh_terms: D006639:Histidine / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D007501:Iron / Q000737:chemistry*; D033862:Iron-Binding Proteins / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D016296:Mutagenesis; D019906:Nuclear Magnetic Resonance, Biomolecular; D000096923:Frataxin
chemical_list: D006639:Histidine; D007501:Iron; D033862:Iron-Binding Proteins; D007506:Iron-Sulfur Proteins; D000096923:Frataxin
references.citation: Structure. 2004 Nov;12(11):2037-48
references.pmid: 15530368
references.citation: Bioinformatics. 2007 Nov 1;23(21):2947-8
references.pmid: 17846036
references.citation: Biochemistry. 2004 Dec 28;43(51):16254-62
references.pmid: 15610019
references.citation: J Biol Chem. 2010 Dec 3;285(49):38486-501
references.pmid: 20889968
references.citation: Biochemistry. 2006 Jun 27;45(25):7767-77
references.pmid: 16784228
references.citation: Chem Rev. 2000 Jan 12;100(1):235-350
references.pmid: 11749238
references.citation: J Biol Chem. 2000 Oct 6;275(40):30753-6
references.pmid: 10900192
references.citation: J Biol Chem. 2009 Aug 14;284(33):21971-21980
references.pmid: 19491103
references.citation: Hum Mol Genet. 2010 Apr 15;19(R1):R103-10
references.pmid: 20413654
references.citation: J Inorg Biochem. 2001 Mar;84(1-2):77-88
references.pmid: 11330484
references.citation: Biochemistry. 1996 Aug 13;35(32):10256-61
references.pmid: 8756680
references.citation: Science. 1996 Mar 8;271(5254):1423-7
references.pmid: 8596916
references.citation: Anal Chem. 2001 May 1;73(9):256A-265A
references.pmid: 11354508
references.citation: FEBS J. 2007 Aug;274(16):4199-210
references.pmid: 17651435
references.citation: J Biomol NMR. 1995 Nov;6(3):277-93
references.pmid: 8520220
references.citation: Mol Microbiol. 2011 Mar;79(5):1260-75
references.pmid: 21208302
references.citation: J Biol Chem. 2000 Dec 29;275(52):41469-75
references.pmid: 11020385
references.citation: J Biol Inorg Chem. 2008 Jun;13(5):825-36
references.pmid: 18425540
references.citation: PLoS One. 2011 Jan 26;6(1):e16199
references.pmid: 21298097
references.citation: J Fluoresc. 2010 Mar;20(2):625-9
references.pmid: 19997966
references.citation: Adv Inorg Biochem. 1984;6:71-111
references.pmid: 6442958
references.citation: Biochemistry. 2012 Sep 4;51(35):6889-91
references.pmid: 22897349
references.citation: Arch Biochem Biophys. 2005 Jan 1;433(1):34-46
references.pmid: 15581564
references.citation: Biochemistry. 2010 Jun 22;49(24):4945-56
references.pmid: 20481466
references.citation: Cell Metab. 2006 Mar;3(3):199-210
references.pmid: 16517407
references.citation: Annu Rev Biophys. 2010;39:387-405
references.pmid: 20462377
references.citation: J Am Chem Soc. 2003 May 21;125(20):6078-84
references.pmid: 12785837
references.citation: Adv Exp Med Biol. 2009;652:247-61
references.pmid: 20225031
references.citation: Trends Genet. 2008 Aug;24(8):398-407
references.pmid: 18606475
references.citation: Methods Enzymol. 1993;226:52-71
references.pmid: 8277880
references.citation: J Biomol NMR. 1999 Sep;15(1):87-8
references.pmid: 10549137
references.citation: Rapid Commun Mass Spectrom. 2003;17(20):2337-42
references.pmid: 14558135
references.citation: Structure. 2000 Jul 15;8(7):695-707
references.pmid: 10903947
references.citation: Biochemistry. 2008 Jul 1;47(26):6917-27
references.pmid: 18540637
references.citation: Biochem J. 2010 Feb 09;426(2):e1-3
references.pmid: 20141512
references.citation: Hum Mol Genet. 2002 Aug 15;11(17):2025-36
references.pmid: 12165564
references.citation: J Biol Inorg Chem. 2007 May;12(4):535-42
references.pmid: 17285345
references.citation: J Am Chem Soc. 2013 Jan 16;135(2):733-40
references.pmid: 23265191
references.citation: J Neurol. 2009 Mar;256 Suppl 1:9-17
references.pmid: 19283345