Initiation, Polypeptide Synthesis, Viral Proteins, RNA, Nucleotide, Codon

Initiation

Initiation -
Each of the three viral proteins is initiated independently from, own initiation site. Polypeptide synthesis is initiated to the AUG initiation codon in all RNA phages, except for the A cistron of MS2 where the initiation codon is GUG.

In group I phages translation does not begin until the l30tb nucleotide, even though AQG and GUG triplets appear in preceding residues.

How do the ribosome’s distinguish between initiator and noninitiator AU a, and" GUG triplets 1 It has been found that initiator AUG and GUG triplets arc located in single stranded RNA regions, or in regions which, are easily, denatured.

Non initiator AUG and GUG triplets on the other hand are located in the hydrogen bonded regions. In addition to the secondary structure of RNA, nucleotide sequences other that AUG or GUG which specify ribosome binding sites also playa role in specifying initiation.

Index >> Bacteriophages - Part Two >> Initiation

Initiation