Transmembrane heme delivery systems.

ABSTRACT: Heme proteins play pivotal roles in a wealth of biological processes. Despite this, the molecular mechanisms by which heme traverses bilayer membranes for use in biosynthetic reactions are unknown. The biosynthesis of c-type cytochromes requires that heme is transported to the bacterial periplasm or mitochondrial intermembrane space where it is covalently ligated to two reduced cysteinyl residues of the apocytochrome. Results herein suggest that a family of integral membrane proteins in prokaryotes, protozoans, and plants act as transmembrane heme delivery systems for the biogenesis of c-type cytochromes. The complete topology of a representative from each of the three subfamilies was experimentally determined. Key histidinyl residues and a conserved tryptophan-rich region (designated the

SUBMITTER: Goldman BS 

PROVIDER: S-EPMC20203 | biostudies-literature | 1998 Apr

REPOSITORIES: biostudies-literature