Identification and preliminary characterization of a 75-kDa hemin- and hemoglobin-binding outer membrane protein of Actinobacillus pleuropneumoniae serotype 1.
The reference strains representing serotypes 1 to 12 of Actinobacillus pleuropneumoniae biotype 1 were examined for their ability to utilize porcine hemoglobin (Hb) or porcine hemin (Hm) as iron sources for growth. In a growth promotion assay, all of the reference strains were able to use porcine Hb, and all strains except 2 were able to use porcine Hm. Using a preliminary characterization procedure with Hm- or Hb-agarose, Hm- and Hb-binding outer membrane proteins (OMPs) of approximately 75 kDa were isolated from A. pleuropneumoniae serotype 1 strain 4074 grown under iron-restricted conditions. Matrix-assisted laser desorption ionization/time-of-flight (MALDI-TOF) analysis revealed a number of common tryptic peptides between the Hb-agarose- and Hm-agarose-purified 75 kDa OMPs, strongly suggesting that these peptides originate from the same protein. A database search of these peptide sequences revealed identities with proteins from various Gram-negative bacteria, including iron-regulated OMPs, transporter proteins, as well as TonB-dependent receptors. Taken together, our data suggest that A. pleuropneumoniae synthesizes potential Hm- and Hb-binding proteins that could be implicated in the iron uptake from porcine Hb and Hm.
Archambault
Marie
M
Groupe de recherche sur les maladies infectieuses du porc, Faculté de médecine vétérinaire, Université de Montreal, St-Hyacinthe, Québec J2S 7C6.
Labrie
Josée
J
Rioux
Clément R
CR
Dumas
France
F
Thibault
Pierre
P
Elkins
Christopher
C
Jacques
Mario
M
D016977:Actinobacillus pleuropneumoniae / Q000378:metabolism*; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000302:isolation & purification* / Q000378:metabolism; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000302:isolation & purification* / Q000378:metabolism; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000302:isolation & purification* / Q000378:metabolism; D006427:Hemin / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D008970:Molecular Weight; D012703:Serotyping; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000662:veterinary; D013552:Swine
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D006454:Hemoglobins; C017206:hemoglobin-binding protein, bacteria; D006427:Hemin; D007501:Iron