Structural and functional reveal of the hemophore in Gram-negative bacteria

Abstract:

Heme is the most abundant iron source in the host. It has been proven that heme was the main nutrient competition aim for the pathogenic bacteria, especially for the bacteria that is not able to synthesize heme. The heme acquisition system of Gram-negative bacteria is consist of hemophore, outer membrane heme receptor, TonB-ExbB-ExbD complex, periplasmic heme-binding proteins, ABC transporter and so on. Hemophore is a type of outer membrane or secreted protein that can extract heme from host hemoprotein and pass it to the outer membrane heme receptors. Up to date, three kinds of hemophores, HasA, HxuA and HmuY, have been identified in some Gram-negative bacteria. In this paper, we described the mechanism of these three types hemophore to capture heme and the interaction with outer membrane heme receptors in detail. It will be helpful for further understanding the function of hemophore and its working mechanism.

Key words:Gram-negative bacteria, Heme, Heme acquisition system, Hemophore, Working mechanism