Protein Synthesis Flashcards
What are the 5 steps of protein synthesis?
Activation. Initiation. Elongation. Termination. Posttraslational modifications.
What is the structure of tRNA?
Cloverleaf: 3’ end of molecule (CCA sequence), The T psi C loop, D loop, anticodon loop
In what loop does the tRNA bind to the ribosome?
T psi C loop
Where is the amino acid binding site on tRNA?
3’ end of the molecule
Isoacceptor tRNA
Recognize different codons, but all have the same animo acid
Amino acyl tRNA synthetases
Couple the amino acid to tRNA via an ester bond. Requires 2 ATP
tRNA f met
Initiation codon for prokaryotes
What initiation factors bind to 30S subunit?
IF 1 and 3
What does IF2 bind to in prokaryotes?
tRNA f met (then binds to AUG at P site)
What is the initiation factor essential for lining up the start codon on the ribosome?
eIF-4E (is an mRNA cap binding factor)
What is the leader sequence for prokaryotes?
Shine-Dalgarno
What determines the efficiency of eukaryotic message translation?
Kozac Consensus Sequence
3 stages of elongation
Binding, peptide bond formation, translocation
Polycistronic mRNA
One mRNA can code for several proteins, and each one might be translated
Polyribosome
Ribosomes + mRNA during translation
What does the phosphorylation of eIF-2 do in eukaryotes?
Inhibits translation
Cycloheximide
Inhibits peptide bond formation in eukaryotic cells
Diphtheria toxin
Catalyzes the reaction of NAD+ w/ eukaryotic elongation factor, resulting in inhibition of translocation
Cloramphenicol
Inhibits peptide bond formation, and can inhibit mitochondrial protein synthesis at high levels in both eukaryotes and prokaryotes
Puromycin
Causes premature termination in both eukaryotes and prokaryotes
Tetracyline
Inhibits elongation in prokaryotes
Sreptomycin
Blocks translation in prokaryotes
Erythromycin
Inhibits translocation in prokaryotes
