12BIS1012013TranslatLect12

Lrodriguez 2013

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Unformatted text preview: n: The Preinitiation Complex ­ ­ ­ ­ ­ ­ Translation initiates with the formation of a Translation preinitiation complex consisting of the preinitiation messenger RNA, a 30S ribosomal subunit and a special aminoacyl-tRNA molecule, tRNAf-met. special Bacterial protein synthesis initiates with Nformyl methionine at a methionine codon, formyl (AUG) near the 5' end of the mRNA. Initiation factors 1 and 3 (IF1 and IF3) bind to bind the 30S subunit and block the binding of the 50S subunit. The anticodon of tRNAf-met base pairs with the initiation codon on the mRNA. IF2 binds to tRNAf-met and brings it to the 30S subunit. Once the tRNAf-met is bound to the 30S subunit. subunit, IF2 hydrolyzes GTP, causing the dissociation of IF1, IF2, and IF3. The 50S subunit contains three sites, E (exit), The P (peptidyl) site and an A (aminoacyl) site. In the 70S initiation complex the tRNAf-met lies in the the peptidyl site. the IF3 IF3 + IF1 + IF3 IF3 IF1 IF1 IF3 IF1 IF3 IF1 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013...
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