Roles of the N- and C-terminal domains of mammalian mitochondrial initiation factor 3 in protein biosynthesis.

ABSTRACT: Bacterial initiation factor 3 (IF3) is organized into N- and C-domains separated by a linker. Mitochondrial IF3 (IF3(mt)) has a similar domain organization, although both domains have extensions not found in the bacterial factors. Constructs of the N- and C-domains of IF3(mt) with and without the connecting linker were prepared. The K(d) values for the binding of full-length IF3(mt) and its C-domain with and without the linker to mitochondrial 28S subunits are 30, 60, and 95 nM, respectively, indicating that much of the ribosome binding interactions are mediated by the C-domain. However, the N-domain binds to 28S subunits with only a 10-fold lower affinity than full-length IF3(mt). This observation indicates that the N-domain of IF3(mt) has significant contacts with the protein-rich small

SUBMITTER: Haque ME 

PROVIDER: S-EPMC2645338 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature