title: Molecular insights into frataxin-mediated iron supply for heme biosynthesis in Bacillus subtilis.
abstract: Iron is required as an element to sustain life in all eukaryotes and most bacteria. Although several bacterial iron acquisition strategies have been well explored, little is known about the intracellular trafficking pathways of iron and its entry into the systems for co-factor biogenesis. In this study, we investigated the iron-dependent process of heme maturation in Bacillus subtilis and present, for the first time, structural evidence for the physical interaction of a frataxin homologue (Fra), which is suggested to act as a regulatory component as well as an iron chaperone in different cellular pathways, and a ferrochelatase (HemH), which catalyses the final step of heme b biogenesis. Specific interaction between Fra and HemH was observed upon co-purification from crude cell lysates and, further, by using the recombinant proteins for analytical size-exclusion chromatography. Hydrogen-deuterium exchange experiments identified the landscape of the Fra/HemH interaction interface and revealed Fra as a specific ferrous iron donor for the ferrochelatase HemH. The functional utilisation of the in vitro-generated heme b co-factor upon Fra-mediated iron transfer was confirmed by using the B. subtilis nitric oxide synthase bsNos as a metabolic target enzyme. Complementary mutational analyses confirmed that Fra acts as an essential component for maturation and subsequent targeting of the heme b co-factor, hence representing a key player in the iron-dependent physiology of B. subtilis.
authors.affiliation: Philipps-University Marburg, Department of Chemistry/Biochemistry, Marburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Mielcarek
authors.affiliation: Philipps-University Marburg, Department of Chemistry/Biochemistry, Marburg, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Blauenburg
authors.affiliation: Philipps-University Marburg, Department of Chemistry/Biochemistry, Marburg, Germany; Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, United States of America.
authors.forename: Marcus
authors.initials: M
authors.lastname: Miethke
authors.affiliation: Philipps-University Marburg, Department of Chemistry/Biochemistry, Marburg, Germany.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Marahiel
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism*; D006418:Heme / Q000096:biosynthesis*; D007501:Iron / Q000378:metabolism*; D033862:Iron-Binding Proteins / Q000502:physiology*; D000096923:Frataxin
chemical_list: D006418:Heme; D007501:Iron; D033862:Iron-Binding Proteins; D000096923:Frataxin
references.citation: Nat Struct Mol Biol. 2009 Apr;16(4):390-6
references.pmid: 19305405
references.citation: J Biol Chem. 2006 Jun 16;281(24):16256-63
references.pmid: 16603772
references.citation: Hum Mol Genet. 2002 Aug 1;11(16):1865-77
references.pmid: 12140189
references.citation: Hum Mol Genet. 2003 Apr 15;12(8):879-89
references.pmid: 12668611
references.citation: Biochemistry. 2004 Dec 28;43(51):16254-62
references.pmid: 15610019
references.citation: Nat Commun. 2010;1:95
references.pmid: 20981023
references.citation: Appl Environ Microbiol. 1992 Jan;58(1):132-42
references.pmid: 1539969
references.citation: FEBS J. 2011 Feb;278(3):470-81
references.pmid: 21166997
references.citation: Curr Opin Chem Biol. 2011 Apr;15(2):312-8
references.pmid: 21288761
references.citation: J Biol Chem. 2004 Jun 18;279(25):25943-6
references.pmid: 15123683
references.citation: Biochemistry. 2007 Jan 9;46(1):87-94
references.pmid: 17198378
references.citation: Crit Rev Biochem Mol Biol. 2006 Sep-Oct;41(5):269-91
references.pmid: 16911956
references.citation: Curr Opin Chem Biol. 1998 Oct;2(5):656-63
references.pmid: 9818193
references.citation: J Inorg Biochem. 2012 Jan;106(1):164-71
references.pmid: 22119809
references.citation: Plant Cell Physiol. 2012 Jul;53(7):1344-54
references.pmid: 22555813
references.citation: Biochemistry. 2012 Apr 10;51(14):3059-66
references.pmid: 22439765
references.citation: FEBS Lett. 2004 Jan 16;557(1-3):215-20
references.pmid: 14741370
references.citation: PLoS One. 2011;6(1):e16199
references.pmid: 21298097
references.citation: J Biol Chem. 1999 Dec 3;274(49):34832-7
references.pmid: 10574955
references.citation: Biochim Biophys Acta. 2013 Oct;1833(10):2267-78
references.pmid: 23764491
references.citation: Mol Cell Neurosci. 2013 Jul;55:50-61
references.pmid: 22917739
references.citation: Structure. 2004 Nov;12(11):2037-48
references.pmid: 15530368
references.citation: Chembiochem. 2011 Sep 5;12(13):2052-61
references.pmid: 21744456
references.citation: J Bacteriol. 2006 May;188(10):3664-73
references.pmid: 16672620
references.citation: Metallomics. 2013 Jan;5(1):15-28
references.pmid: 23192658
references.citation: Chem Commun (Camb). 2010 Feb 7;46(5):719-21
references.pmid: 20087498
references.citation: J Am Chem Soc. 2003 May 21;125(20):6078-84
references.pmid: 12785837
references.citation: IUBMB Life. 2012 Jan;64(1):56-63
references.pmid: 22095894
references.citation: Trends Biochem Sci. 2006 Mar;31(3):135-42
references.pmid: 16469498
references.citation: Eur J Biochem. 1994 Feb 15;220(1):201-8
references.pmid: 8119288
references.citation: Nat Struct Biol. 2001 Feb;8(2):156-60
references.pmid: 11175906
references.citation: J Biol Chem. 2010 Aug 27;285(35):26753-9
references.pmid: 20522548
references.citation: FEBS Lett. 2013 Jan 16;587(2):206-13
references.pmid: 23220087
references.citation: Mitochondrion. 2009 Apr;9(2):130-8
references.pmid: 19460301
references.citation: Biochemistry. 2012 Mar 27;51(12):2506-14
references.pmid: 22352884
references.citation: Biochim Biophys Acta. 2012 Sep;1823(9):1491-508
references.pmid: 22609301
references.citation: Mol Microbiol. 2006 Sep;61(6):1413-27
references.pmid: 16889643
references.citation: Anal Biochem. 1976 May 7;72:248-54
references.pmid: 942051
references.citation: EMBO Rep. 2003 Sep;4(9):906-11
references.pmid: 12947415
references.citation: Biochim Biophys Acta. 2007 Jul;1772(7):773-80
references.pmid: 17499976
references.citation: Antioxid Redox Signal. 2006 Mar-Apr;8(3-4):506-16
references.pmid: 16677095
references.citation: J Biol Chem. 2003 Dec 19;278(51):51415-21
references.pmid: 14504287
references.citation: J Am Soc Mass Spectrom. 2012 Sep;23(9):1512-21
references.pmid: 22692830
references.citation: Coord Chem Rev. 2011 Apr 1;255(7-8):688-699
references.pmid: 21499539
references.citation: Cell Mol Life Sci. 2000 Dec;57(13-14):1909-26
references.pmid: 11215517
references.citation: Protein J. 2013 Mar;32(3):183-96
references.pmid: 23463383
references.citation: Biochemistry. 2013 Sep 3;52(35):6085-96
references.pmid: 23909240
references.citation: J Biol Chem. 2006 Jun 16;281(24):16493-501
references.pmid: 16613854
references.citation: J Biol Chem. 2003 Aug 15;278(33):31340-51
references.pmid: 12732649