Differential utilization by Haemophilus influenzae of haemoglobin complexed to the three human haptoglobin phenotypes.
Haemophilus influenzae has an absolute requirement for heme, which may be supplied as the haemoglobin-haptoglobin complex. Utilization of haemoglobin-haptoglobin by H. influenzae is mediated by a family of proteins termed the haemoglobin-haptoglobin binding proteins (Hgps), of which a given strain may contain up to four genes. Human haptoglobin occurs in three phenotypes (1-1, 2-1 and 2-2). Using mutant derivatives of an H. influenzae type b strain that expressed single Hgps we analysed the ability of each Hgp to utilize haemoglobin complexed to the various haptoglobin phenotypes. A strain expressing only HgpB was able to utilize haemoglobin bound to all haptoglobin phenotypes significantly better than strains expressing either HgpA or HgpC.
Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Daniel J
DJ
Morton
Timothy M
TM
VanWagoner
Thomas W
TW
Seale
Paul W
PW
Whitby
Terrence L
TL
Stull
D001426:Bacterial Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D006192:Haemophilus Infections / Q000382:microbiology* / Q000821:virology; D019741:Haemophilus influenzae type b / Q000254:growth & development* / Q000378:metabolism; D006242:Haptoglobins / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D010641:Phenotype; D018709:Statistics, Nonparametric
D001426:Bacterial Proteins; D002352:Carrier Proteins; D006242:Haptoglobins; D006454:Hemoglobins; C035492:haptoglobin-hemoglobin complex; C017206:hemoglobin-binding protein, bacteria