??? ??? 4??

1. ??????? ??? ??
¢Ù aminoacyl-tRNA? ??(????? ???)

- aminoacyl-tRNA synthetase (aaRS)? ATP? ???? tRNA? 3` end (-CCAOH)? ???? adenosine? 3`- (or 2`-) OH?? ???? amino acid? ester????
- ? amino acid? tRNA (? ? ?? ?? ??)? ????? aaRS? ? ???

- aaRS? ??
1. ????? ???: amino acid + ATP + aaRS ¡ú aminoacyl AMP-aaRS + PPi (? ??? Mg2+? ??)
2. tRNA? amino acid? ??: aminoacyl AMP-aaRS + tRNA ¡ú aminoacyl tRNA + AMP + aaRS
3. ??? ??? ????? ??? ??

- ??????? ???? ????? ?? fMet-tRNAfMet??.

¢Ú ?????initiation complex? ??

????? ?? ??? ????? mRNA? ???? ??? ????, ??? ? ?? ??? ???? ??? ??? ?????-tRNA(initiator aminoacyl-tRNA)? ????. ? ?? ??? ?? ????? ?? ?? mRNA? ?? 30? ??? ??????? ?? ?? ?? ??.
- initiation factor :IF-1, IF-2, IF-3
- 30S + IF-3 (30S? 50S? ????, IF-1? IF-3? ??? ???? ??? ??)

- 30S-IF-3 + mRNA : 30S-IF-3? mRNA? 5¡® ???? ??? ?, 3¡¯?? ??. 30S? 16S rRNA? 3¡® ??? mRNA? start codon ???? Shine-Dalgarno ??? ?? (start codon? peptidyl-tRNA-binding site (P-site)? ???? ?)