Send to

Choose Destination
See comment in PubMed Commons below
Infect Immun. 2005 Aug;73(8):5086-92.

Heme transfer from streptococcal cell surface protein Shp to HtsA of transporter HtsABC.

Author information

Veterinary Molecular Biology, Montana State University, P.O. Box 173610, Bozeman, MT 59717, USA.


Human pathogen group A streptococcus (GAS) can take up heme from host heme-containing proteins as a source of iron. Little is known about the heme acquisition mechanism in GAS. We recently identified a streptococcal cell surface protein (designated Shp) and the lipoprotein component (designated HtsA) of an ATP-binding cassette (ABC) transporter made by GAS as heme-binding proteins. In an effort to delineate the molecular mechanism involved in heme acquisition by GAS, heme-free Shp (apo-Shp) and HtsA (apo-HtsA) were used to investigate heme transfer from heme-containing proteins (holo proteins) to the apo proteins. In addition, the interaction between holo-Shp and holo-HtsA was examined using native polyacrylamide gel electrophoresis. Heme was efficiently transferred from holo-Shp to apo-HtsA but not from holo-HtsA to apo-Shp. Apo-Shp acquired heme from human hemoglobin, and holo-Shp and holo-HtsA were able to form a complex, suggesting that Shp actively relays heme from hemoglobin to apo-HtsA. These findings demonstrate for the first time complex formation and directional heme transfer between a cell surface heme-binding protein and the lipoprotein of a heme-specific ABC transporter in gram-positive bacteria.

[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center