Translation Pt. 2

Aminoaceyl tRNA synthetase

“Charge” the tRNA by adding the appropriate amino acids

“Charged”

tRNA has an amino acid attached

Shine Dalgarno sequence

Sequence on the mRNA that binds with the small ribosomal subunit

What transports charged tRNAs

EF-Tu

How does the large ribosomal subunit help with elongation

Catalyzes the formation of a peptide bond between amino acid of p-site tRNA and amino acid of a-site tRNA

What supplies the energy to form new peptide bonds

High-energy ester bonds between a tRNA and its cognate amino acid

Translocation

Ribosomal complex moves down mRNA by one codon

Release factor

Binds to the a-site and stimulates hydrolysis of the polypeptide from the peptidyl tRNA, leading to its release from the translation complex

How many release factors are there

3

What stop codons is release factor 1 specific to

UAG and UAA

What stop codon is release factor 2 specific to

UGA and UAA

Release factor 3

Binds to the ribosome and the tRNA is released from the p-site of the ribosome; dissociates into its subunits

Polycistronic

mRNA that encodes 2+ proteins

What does the small ribosomal subunit associate with in eukaryotes

5’ cap

Scanning

Ribosome moves in 5’ to 3’ direction along 5’ UTR to find the start codon

Kozak sequence

Many eukaryotes have a sequence 5 base pairs upstream of the start codon that help position AUG into the p-site

Closed-loop translation

Poly-A binding proteins also bind to one of the eukaryotic initiation factors (elF4G) which in turn binds to the 5’ cap