Metalloproteins: structure and function-Structure and function of heme-binding proteins in heme-uptake systems of gram-positive bacteria

摘要

Some bacteria, especially pathogenic bacteria, can be used heme (iron protoporphyrin complex) as an iron source, which have several heme uptake systems. An ABC-type heme transporter system is widely used for heme acquisition, which consists of an ATP-binding protein, heme permease, and heme-binding protein (substrate-binding protein). In this work, we have studied the structural and functional relationships of two heme-binding proteins, HupD and HmuT in Listeria monocytogenes and Corynebacterium glutamicum, respectively. HupD and HmuT act as a heme-binding protein in the heme acquisition systems, HupDGC and HmuTUV for Listeria monocytogenes and Corynebacterium glutamicum, respectively. Heme captured in HupD/HmuT is transferred into cytoplasm by the ABC-type HupDG/HmuUV heme transporter, but the detailed molecular mechanisms of heme transport in these systems remain to be elucidated.