分子生物学（杨洋）第七章 翻译-2.ppt

文档介绍：Outline
Topics 1-4: ponents of translation machinery.
T1-mRNA; T2-tRNA; T3-Attachment of amino acids to tRNA (aminoacyl-tRNA synthetases); T4-ribosome
Topic 5-7: Translation process.
T5-initiation; T6-elongation; T7-termination.
11/30/2018
1
Translation processT5: Initiation of translationT6: Elongation of translationT7: termination of translation
11/30/2018
2
Overview of the events of translation
Termination
Elongation
Initiation
11/30/2018
3
Topic 5: Initiation of translation
11/30/2018
4
Three events must occur:
ribosome must be recruited to mRNA
2. a charged tRNA must be placed into
the P site of ribosome
3. the ribosome must be precisely
positioned over the start codon
11/30/2018
5
start codon
One-base shift will result in the synthesis of
completely unrelated polypeptide
11/30/2018
6
The different structure of prokaryotic and eukaryotic mRNA results in distinctly different means of translational initiation
11/30/2018
7
5-1 prokaryotic mRNAs are recruited to the small subunit by base pairing to rRNA
mRNA
mRNA/ small
plex
11/30/2018
8
5-2 A specialized tRNA charged with modified methionine binds directly to prokaryotic small subunit
Initiator tRNA:
fMet-tRNA
(甲酰甲硫氨酸)
fMet-tRNAfMet
11/30/2018
9
modified methionine
(甲酰甲硫氨酸)
11/30/2018
10