1-2 Prokaryotic mRNAs have a ribosome binding site (RBS)that recruits the translational machinery 2025/5/15 1616
2025/5/15 1616 1-2 Prokaryotic mRNAs have a ribosome binding site (RBS) that recruits the translational machinery
Ribosome binding site(RBS,核糖体结合位点)orSD- sequence (SD)in prokaryotic mRNA,complementary with the sequence at the 3'end of 16S rRNA. 16S rRNA 3UUCCUCCACUAGS 5NNNNGGAGGNNNNNNNAUGNN3 RBS start stop RBS start stop RBS start stop 3 PPP 5-9 bases 090000000000000 G00000000000000 000000000000000 structure of prokaryotic mRNA
2025/5/15 1717 Ribosome binding site (RBS，核糖体结合位点) or SDsequence（SD序列） in prokaryotic mRNA, complementary with the sequence at the 3’ end of 16S rRNA. structure of prokaryotic mRNA
Initiation codon araB -UUUGGAUGGAGUGAAACGAUGGCGAUU- galE -AGCCUAAUGGAGCGAAUUAUGAGAGUU- lacl -CAAUUCAGGGUGGUGAUUGUGAAACCA- lacZ -UUCACACAGGAAACAGCUAUGACCAUG QB phage replicase -UAACUAAGGAUGAAAUGCAUGUCUAAG- X174 phage A protein -AAUCUUGGAGGCUUUUUUAUGGUUCGU- R17 phage coat protein -UCAACCGGGGUUUG AGCAUGGCUUCU- Ribosomal S12 -AAAACCAGGAGCI JUAAUGGCAACA- Ribosomal L10 -CUACCAGGAGCA AAGCUAAUGGCUUUA- trpE -CAAAAUUAGAGAAUAACAAUGCAAACA- trp leader -GUAAAAAGGGUAUCGACAAUGAAAGCA- 3'end of 16S rRNA 3 HOAUUCCUCCACUAG- 51 Figure 26-26.Some translation initiation sequences recognized by E.coll ribosomes. [After Steitz,J.A.,in Chambliss,G.Craven,G.R.Davies,J.,Davis,K.Kahan,L.and Nomura,M. (Eds.),Ribosomes.Structure,Function and Genetics,pp.481-482,University Park Press (1979).] Copyright 1999 John Wiley and Sons,Ine.All rights reserved. 2025/5/15 18
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3OH G 3'end of A 16S rRNA 8 C UCCUCCA 6 GAUUCCUAGGAGGUUUGACCUAUGCGAGCUUUUAGU-Messenger RNA fMet'-Arg'-Ala-Phe-Ser-Polypeptide The ribosome binding site is frequently called the Shine- Dalgarno sequence. 2025/5/15 19
2025/5/15 19 The ribosome binding site is frequently called the ShineDalgarno sequence
SD sequence(SD序列) in prokaryotes,about 10nt upstream of the initiation codon in mRNA,there is a sequence riched in purines,all or part of this sequence:AGGAGGU,which is complementary to the boldfaced part of the sequence riched in pyrimidines at the very 3'-end of 16S rRNA in the ribosome and helps recruit the ribosome to the mRNA to initiate protein synthesis by aligning it with the start codon.it has come to be called the Shine-Dalgarno sequence,or SD sequence, in honor of its discoverers. 20251515 20
2025/5/15 20 ◼ SD sequence（SD序列）: in prokaryotes, about 10nt upstream of the initiation codon in mRNA, there is a sequence riched in purines, all or part of this sequence: AGGAGGU, which is complementary to the boldfaced part of the sequence riched in pyrimidines at the very 3’-end of 16S rRNA in the ribosome and helps recruit the ribosome to the mRNA to initiate protein synthesis by aligning it with the start codon. it has come to be called the Shine-Dalgarno sequence, or SD sequence, in honor of its discoverers