PROKARYOTIC TRANSLATION

PROKARYOTIC - tRNA is modified it contains a formyl group at its amino(N group N-formylmethionine tRNAfMet In prokaryotic mRNA the first AUG at the

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
PROKARYOTIC TRANSLATION In E. coli and other prokaryotes the mRNA is transcribed without prior processing. But translation does not start directly at the 5' end of the mRNA. Instead we find an untranslated region at the 5' end called 5' untranslated region or 5' UTR . Translation always starts with the amino acid methionine and therefore usually at an AUG codon: All newly synthesized proteins contain a methionine at their amino terminus (often cleaved off after synthesis). In E. coli and many other prokaryotes the tRNA for methionine at start of translation different from the tRNAMet used in the middle of the coding sequence: specific initiator tRNA . And additionally the methionine contained in the initiator
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: tRNA is modified, it contains a formyl group at its amino (N) group ( N-formylmethionine ): tRNAfMet . In prokaryotic mRNA, the first AUG at the 5' end is not necessarily the start site for translation. Instead the start codon is always preceeded by a sequence specifying the AUG as start site. The specific sequence ( AGGAGGU ) is called Shine-Dalgarno sequence after its discoverers. The sequence base pairs with a complementary sequence near the 3' terminus in the 16S rRNA (part of the small, 30S ribosomal subunit). This specific base pairing alines the mRNA and the ribosome....
View Full Document

This document was uploaded on 11/03/2011 for the course BIOLOGY MCB2010 at Broward College.

Ask a homework question - tutors are online