Open AccessDifferential utilization by Haemophilus influenzae of haemoglobin complexed to the three human haptoglobin phenotypes
Author(s) -
Morton Daniel J.,
VanWagoner Timothy M.,
Seale Thomas W.,
Whitby Paul W.,
Stull Terrence L.
Publication year - 2006
Publication title -
fems immunology & medical microbiology
Language(s) - English
Resource type - Journals
eISSN - 1574-695X
pISSN - 0928-8244
DOI - 10.1111/j.1574-695x.2006.00052.x
Subject(s) - haptoglobin , haemophilus influenzae , phenotype , biology , microbiology and biotechnology , strain (injury) , mutant , heme , gene , bacteria , genetics , immunology , biochemistry , enzyme , anatomy
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.