The upcoming discussion will update you about the differences between protein synthesis in prokaryotes and protein synthesis in eukaryotes.
Protein Synthesis in Prokaryotes:
1. Synthesis of three types RNA is controlled by a single RNA polymerase.
2. Involves 70S ribosomes with SOS and 505 subunits.
3. The timing of transcription and translation can overlap.
4. mRNA needs no modification before translation.
5. Special initiator tRNA participates called Met-tRNAf or Met – tRNAi.
6. Starting amino acid is N-formyl methionine.
7. Have several initiation and termination sites.
8. The ribosomal binding site (RBS) on mRNA is the Shine-Dalgarno sequence that lies -10 nucleotides ahead of the initiation codon.
9. Three initiation factors (IF-1, IF-2, and IF-3) are required for chain initiation.
10. There are three chain elongation factors (EF-Tu, EF-Ts, and EP-G).
11. There are two release factors (RF-1 or RF-2 and RF-3) for recognition of termination codons.
12. Genetic code is same in every prokaryotic organism.
Protein Synthesis in Eukaryotes:
1. Several RNA polymerase are responsible for synthesis of cellular RNA.
2. Involves SOS ribosomes with 40S and 60S sub- units.
3. There is no overlapping of transcription and translation.
4. The pre mRNA or hn mRNA undergoes modification before it is translated.
5. No special initiator tRNA is involved.
6. Starting amino acid is methionine.
7. Have single initiation and termination site.
8. The RBS is Kozak sequence that is centered around the start codon
9. Several initiation factors (eIF-2, (eIF-2, eIF-2al, eIF-a2, eIF-a3) are involved in chain initiation.
10. There are two chain elongation factors (EF-1 and EF-2).
11. There is a single release factor eRF for recognition of three termination codons (UAA, UAG and UGA).
12. Genetic code may differ in mitochondria and chloroplast.