title: The NEAT Domain-Containing Proteins of Clostridium perfringens Bind Heme.
abstract: The ability of a pathogenic bacterium to scavenge iron from its host is important for its growth and survival during an infection. Our studies on C. perfringens gas gangrene strain JIR325, a derivative of strain 13, showed that it is capable of utilizing both human hemoglobin and ferric chloride, but not human holo-transferrin, as an iron source for in vitro growth. Analysis of the C. perfringens strain 13 genome sequence identified a putative heme acquisition system encoded by an iron-regulated surface gene region that we have named the Cht (Clostridium perfringens heme transport) locus. This locus comprises eight genes that are co-transcribed and includes genes that encode NEAT domain-containing proteins (ChtD and ChtE) and a putative sortase (Srt). The ChtD, ChtE and Srt proteins were shown to be expressed in JIR325 cells grown under iron-limited conditions and were localized to the cell envelope. Moreover, the NEAT proteins, ChtD and ChtE, were found to bind heme. Both chtDE and srt mutants were constructed, but these mutants were not defective in hemoglobin or ferric chloride utilization. They were, however, attenuated for virulence when tested in a mouse myonecrosis model, although the virulence phenotype could not be restored via complementation and, as is common with such systems, secondary mutations were identified in these strains. In summary, this study provides evidence for the functional redundancies that occur in the heme transport pathways of this life threatening pathogen.
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Jocelyn M
authors.initials: JM
authors.lastname: Choo
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Jackie K
authors.initials: JK
authors.lastname: Cheung
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Wisniewski
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
authors.forename: David L
authors.initials: DL
authors.lastname: Steer
authors.affiliation: Victorian Bioinformatics Consortium, Monash University, Clayton, Victoria, Australia.
authors.forename: Dieter M
authors.initials: DM
authors.lastname: Bulach
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Hiscox
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Anjana
authors.initials: A
authors.lastname: Chakravorty
authors.affiliation: Victorian Bioinformatics Consortium, Monash University, Clayton, Victoria, Australia.
authors.forename: A Ian
authors.initials: AI
authors.lastname: Smith
authors.affiliation: School of Medicine, University of Tasmania, Hobart, Tasmania 7000, Australia.
authors.forename: David A
authors.initials: DA
authors.lastname: Gell
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Julian I
authors.initials: JI
authors.lastname: Rood
authors.affiliation: Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC 3800, Australia.
authors.forename: Milena M
authors.initials: MM
authors.lastname: Awad
mesh_terms: D015153:Blotting, Western; D003016:Clostridium perfringens / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006418:Heme / Q000378:metabolism*; D011485:Protein Binding; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014158:Transcription, Genetic
chemical_list: D006418:Heme