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.
Morton
Daniel J
DJ
Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
VanWagoner
Timothy M
TM
Seale
Thomas W
TW
Whitby
Paul W
PW
Stull
Terrence L
TL
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