The beginning of peptide chain synthesis.

. The namenucleoprotein body size sub-base, mRNA starting tRNA and starting factors are involved in the beginning of peptide chain synthesis.1, E. coli cell translation starting complex formation process: (1) RNA body 30S sub-base attached to the mRNA starting signal site: each mRNA in the pronuclelobacter has its nuclear glycosome binding site, which is located in the upper reaches of AUG 8-13
nucleotides
a short film called SD sequence. This sequence complements exactly one part of the 16s rRNA3' end of the 30S sub-base, so the SD sequence is also called the RNA binding sequence, which means that the RNA can select the correct location on the mRNA to start the synthesis of the peptide chain. The binding reaction is mediated by the starting factor 3 (IF-3), and IF-1 promotes the binding of IF-3 with small sub-base, so the IF3-30S sub-base-mRNA ternate complex is formed first.(2) 30S pre-start complex formation: Under the action of the starting factor 2, methyl methylaminate starting tRNA is combined with AUG in the mRNA molecule, i.e. the cocoon is paired with the anti-cocoon, while IF3 falls off the trol matter complex to form a pre-30S starting complex, i.e. 2-3S sub-mRNA-fMet-tRNafmet complex, which requires GTP and Mg2.(3) 70S starting complex: 50S sub-base above the 30S pre-start complex binding, while IF2 falls off to form a 70S starting complex, i.e. 30S sub-mRNA-50S sub-base-mRNA-fMet-tRNAfmet complex. At this point fMet-tRNAfmet occupies a peptide bit of 50S sub-base. The A-bit is empty and the corresponding aminotin tRNA, which corresponds to the second password in the mRNA, enters the extension phase, as shown in Figures 18-8 and 18-9 above.Figure 18-8 The formation of E. coli starting complex 2, the beginning of the synthesis of the
protein
of the endocyst cells the formation of the starting complex of the protein synthesis of the endocyst cell requires more involvement of the starting factor, so the starting process is more complex.(1) requires a specific starting tRNA, i.e., -tRNAfmet, and does not require N-end methylation. Nearly 10 eukaryote Start factors (eukaryote Startion factor, eIF) (2) starting complexes have been found to form a hat structure upstream of the mRNA5' end AUG, (except for some viral mRNAs) (3) ATP hydrolysing to provide ADP with the energy needed for mRNA binding. The formation process of the primary complex of the celeriac cell is: the translation is also started by eIF-3 binding on the 40S sub-base and promoting the disintegration of 80S RNA out of 60S sub-base, while eIF-2 in the auxiliary eIF-2 action, combined with Met-tRNAfmet and GTP, and then through eIF-3 and eIF-4C action, first binding to 40S sub-base, and then binding to 40S sub-base.mRNA binds to 40S sub-base, in addition to eIF-3 participation, eIF-1, eIF-4A and eIF-4B are required and supplied by ATP sub-solution to ADP and Pi, which are transferred to the small sub-base by combining cap binding factors with mRNA caps. However, no S-D sequences were found at the mRNA5' end that could be paired with small sub-base 18SRNAs. It is currently believed that by combining the cap, mRNA moves downstream on the small sub-base and scans, allowing the starting password ONG on the mRNA to be fixed in the anti-password position of Met-tRNAfmet for translation starting.18-9 Image 18-9 Action of translation im E.cole.The programme tRNA, tRNAMetf, is represented by the blue line, the anticodon is the horizontal short line. The fMet-tRNAMetf is delivered to the 30s subunit by IF2. NNN means any codon (N for any nucleotie). Note.The ribosome also has an exit site not show in the diagram. This site will be discussed later.the effect of eIF-5, it is able to combine Met-tRNAfmet, GTP and mrNAR40S sub-sub-base with 60S large sub-base to form an 80S complex. eIF-5 has GTP enzyme activity, catalytic GTP hydrolysis for GDP and Pi, and is beneficial for other starting factors to fall off the 40S sub-base surface, thus helping to combine 40S with 60S two sub-base, and finally activated by eIF-4D to become an active 80SMet-tRNAfmet-mRNA starting complex.18-10 and Figure 18-11 for the generation of the starting complex for the translation of uergenic nucleocytes.18-10 Eukaryotes, the formation of the starting complex for eukaryotes18-11 Simplified diagram of the starting complex. Note that os eukaryote startionion factors besides elF2 are involved .tRNAMeti, starting RNA.e1F2 is the eukaryotic bootion factor to if2 in prokaryotes.
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