1-2Prokaryotic mRNAs P have a site that recruits the G translational machinery 2 1-3 Eukaryotic mRNA are modified at their 5 and 3 ends to facilitate translation
2021/1/21 17 1-2 Prokaryotic mRNAs have a ribosome binding site that recruits the translational machinery Message RNA 1-3 Eukaryotic mRNA are modified at their 5’ and 3’ ends to facilitate translation
a Ribosome binding site(RBs)or SD sequence in prokaryotic mRNA, complementary with the sequence at the 3′ end of16 SrRNA UCCUCCACUAG 5 16SrRNA a 5 nnnNGGAGGNNNNNNNaUGNN 3 RBS start stop RBS start stop RBS start stop 5 PPP 5-9 bases 00000000000 00000 Fig 14-2-a structure of prokaryotic mRNA
2021/1/21 18 ◼ Ribosome binding site (RBS) or SDsequence in prokaryotic mRNA, complementary with the sequence at the 3’ end of 16S rRNA. Fig 14-2-a structure of prokaryotic mRNA
5 NNRNNNAUGGNN3∠ Kozak sequence start stop 5 AUG 口 AAAAA3 5'cap Fig 14-2-b a Eukaryotic mRNA uses a methylated cap to recruit the ribosome. Once bound the ribosome scans the mrna in a5′-3′ direction to find the aug start codon a Kozak sequence increases the translation efficiency Poly-A in the 3 end promotes the efficient recycling of ribosomes
2021/1/21 19 Once Kozak sequence ◼ Eukaryotic mRNA uses a methylated cap to recruit the ribosome. Once bound, the ribosome scans the mRNA in a 5’-3’ direction to find the AUG start codon. ◼ Kozak sequence increases the translation efficiency. ◼ Poly-A in the 3’ end promotes the efficient recycling of ribosomes Fig 14-2-b
polyA tai Ewvvvvvvvvvvvvv poly-A binding 5 cap start (AUG) protein stop(AGU) Fig 1-29 Copyright 2004 Pearson Education, Inc, publishing as Benjamin Cummings
2021/1/21 20 Fig 1-29
2021/1/21 Topic 2: tRNA At the heart of protein synthesis is the translation of nucleotide sequence information into amino acids. This work is accomplished by tRNA 21
2021/1/21 21 Topic 2: tRNA At the heart of protein synthesis is the translation of nucleotide sequence information into amino acids. This work is accomplished by tRNA