tRNA的结构 Amino Acid link N2H Amino Acid tRNA Acce ptor arm a Anticodon -- DXAGOGD Anticodon 1oop Fig. The primary struture of yeast alanine tRNA(tRNA") the first such sequence determined. This molecule is sythesized from the nucleotides A, C,G, and u, but some of the nucleotides, shown in red, are modified after systhesis D=dihydrouridine, I= inos ne. v= pseudouridine. and m= methyl group. The primary structure can be diagrammed as a cloverleaf consisting of four base-paired stems and three loops: the D loop (for dihydrouridine, a virtually constant constituent of this loop): the anticodon loop: and the TCG loop (for thymidylate, pseudouridylate, cytidylate, and guanylate which are almost always present in sequene in this loop) nt of an aino acid to the acceptor arm yields an aminoacyl-tRNA
tRNA 的结构
在核糖体上合成蛩白质 (1)启动阶段
在核糖体上合成蛋白质 （1）启动阶段
肽链的延伸阶段 “受位”(A)和“给位” H4 Peptide bond 50s peaty transferase CEOE N-C-C-0 M:-C-c:0 e°H H P site iA site 20s 点cc UAC AGG 5
肽链的延伸阶段 -------“受位” （A）和“给位” （P）
肽链的延伸阶段和终止阶段 进位反应 转位反应 Many amino acids Released 移位反应 Relea polypeptide chain 终止阶段 )-( W 5L MG UMGDIx s1 L3 5'LMG UA L-3 5'L1AAGUAHLL3 Stop codon 0 Stop codon is 2 0 Polypeptide chain O Components separate encountered binds to stop codon is releasd
*进位反应 *转位反应 *移位反应 *终止阶段 肽链的延伸阶段和终止阶段
Ribosome Growing polypeptide chain RNA RNA4 CAG mRNA aa]. tRNA7 IGAAAUCGG Movement of ribosome Codon Codon Codon Codon Codon Codon Codon aa aa aa aa