PROSITE documentation PDOC00723Initiation factor 3 signature
Initiation factor 3 (IF-3) (gene infC) [1] is one of the three factors required for the initiation of protein biosynthesis in bacteria. IF-3 is thought to function as a fidelity factor during the assembly of the ternary initiation complex which consist of the 30S ribosomal subunit, the initiator tRNA and the messenger RNA. IF-3 binds to the 30S ribosomal subunit; it is a basic protein of 141 to 212 residues.
The chloroplast initiation factor IF-3(chl) is a protein that enhances the poly(A,U,G)-dependent binding of the initiator tRNA to chloroplast ribosomal 30s subunits. In its mature form it is a protein of about 400 residues whose central section is evolutionary related to the sequence of bacterial IF-3 [2].
As a signature pattern we selected a highly conserved region located in the central section of bacterial IF-3 and of IF-3(chl).
Last update:December 2001 / Pattern and text revised.
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PROSITE method (with tools and information) covered by this documentation:
| 1 | Authors | Liveris D. Schwartz J.J. Geertman R. Schwartz I. |
| Title | Molecular cloning and sequencing of infC, the gene encoding translation initiation factor IF3, from four enterobacterial species. | |
| Source | FEMS Microbiol. Lett. 112:211-216(1993). | |
| PubMed ID | 8405963 |
| 2 | Authors | Lin Q. Ma L. Burkhart W. Spremulli L.L. |
| Title | Isolation and characterization of cDNA clones for chloroplast translational initiation factor-3 from Euglena gracilis. | |
| Source | J. Biol. Chem. 269:9436-9444(1994). | |
| PubMed ID | 8144528 |
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