3izz | pdb_00003izz
Models for ribosome components that are nearest neighbors to the bovine mitochondrial initiation factor2 bound to the E. Coli ribosome
Structural highlights
FunctionRL14_ECOLI This protein binds directly to 23S ribosomal RNA. In the E.coli 70S ribosome (PubMed:12809609) it has been modeled to make two contacts with the 16S rRNA of the 30S subunit, forming part of bridges B5 and B8, connecting the 2 subunits. Although the protein undergoes significant rotation during the transition from an initiation to and EF-G bound state, the bridges remain stable. In the 3.5 A resolved structures (PubMed:16272117) L14 and L19 interact and together make contact with the 16S rRNA in bridges B5 and B8.[1] Can also interact with RsfA, in this case bridge B8 probably cannot form, and the 30S and 50S ribosomal subunits do not associate, which represses translation.[2] Publication Abstract from PubMedMitochondria have their own translational machineries for the synthesis of thirteen polypeptide chains that are components of the complexes that participate in the process of oxidative phosphorylation (or ATP generation). Translation initiation in mammalian mitochondria requires two initiation factors, IF2(mt) and IF3(mt), instead of the three that are present in eubacteria. The mammalian IF2(mt) possesses a unique 37 amino acid insertion domain, which is known to be important for the formation of the translation initiation complex. We have obtained a three-dimensional cryoelectron microscopic map of the mammalian IF2(mt) in complex with initiator and the eubacterial ribosome. We find that the 37 amino acid insertion domain interacts with the same binding site on the ribosome that would be occupied by the eubacterial initiation factor IF1, which is absent in mitochondria. Our finding suggests that the insertion domain of IF2(mt) mimics the function of eubacterial IF1, by blocking the ribosomal aminoacyl-tRNA binding site (A site) at the initiation step. Insertion domain within mammalian mitochondrial translation initiation factor 2 serves the role of eubacterial initiation factor 1.,Yassin AS, Haque ME, Datta PP, Elmore K, Banavali NK, Spremulli LL, Agrawal RK Proc Natl Acad Sci U S A. 2011 Mar 8;108(10):3918-23. Epub 2011 Feb 22. PMID:21368145[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
| ||||||||||||||
