The RBS, typically located 3–9 bp on the 5’side of the start codon, is complementary to a sequence located near the 3’end of one of the ribosomal RNA components, the 16S ribosomal RNA (rRNA).

TLS Online TPP Program

#Id: 7091

#Unit 3. Fundamental Processes

binding by a ribosome, many prokaryotic ORFs contain a short sequence upstream (on the 5’ side) of the start codon called the ribosome binding site (RBS). This element is also referred to as a polypurine stretch Shine–Dalgarno sequence.

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#Unit 3. Fundamental Processes

It is complementary to a highly conserved sequence close to the 3’ end of 16S rRNA.

The rRNA sequence is the hexamer:

3’. . . U C C U C C . . . 5’

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#Unit 3. Fundamental Processes

 5’-AUGA-3’ is sequence between overlapping ORFs is known as translational coupling.

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#Id: 7094

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 7095

#Unit 3. Fundamental Processes

 A series of 3 G-C pairs in the stem that precedes the loop containing the anticodon is unique to tRNAf Met. These base pairs are required to allow the fMet- tRNAf to be inserted directly into the P site.

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#Unit 3. Fundamental Processes

Formylation is not strictly necessary because nonformylated Met-tRNAf can function as an initiator.