分子生物学第九章蛋白质合成
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Chapter 9
Protein synthesis
Introduction
Coding region编码区 is a part of the gene that represents a protein sequence. Coding strand 编码链of DNA has the same sequen ce as mRNA. template strand模板链 of double-stranded DNA i s the one that is used to specify the sequence of a complementary single strand of RNA. (The non-template strand is identical in sequence t o the RNA product.) Transcription 转录is synthesis of RNA on a DNA template. Translation 翻译is synthesis of protein on the mRNA template.
A polyribosome多核糖体consists of an mRNA being translated simultaneously by several ribosomes m oving in the direction from 5’-3’ . Each ribos ome has two tRNA molecules, one carrying the nas cent amino acid初生氨基酸, the second carrying t he next amino acid to be added 添加氨基酸.
The meaning of tRNA is determined by it s anticodon and not by its amino acid.
Messenger RNA is t ranslated by ribos omes 核糖体
A ribosome consi sts of two subun its亚基.
Loop 环is a single-stranded region of a hairpin发夹 in R NA (or single-stranded DNA); corresponds to the sequen ce between inverted repeats 反向重复in duplex DNA.
Aminoacyl-tRNA synthetases are enzymes responsible for c ovalently linking amino acids to the 2′- or 3′-OH po sition of tRNA.
Anticodon反密码子 is a trinucleotide三核苷酸sequence in tRNA which is complementary to the codon in mRNA and e nables the tRNA to place the appropriate amino acid in response to the codon.
Transfer RNA is the adapte r
Aminoacyl氨酰-tRNA is transfer RNA carrying an amino aci d; the covalent 共价linkage is between the NH2 group o f the amino acid and either the 3′- or 2′-OH group o f the terminal base of the tRNA.
A tRNA has the dual properties of an ada ptor that recognizes both the amino acid and codon. The adeno sine腺苷at 3’ end i s covalently linked to an amino acid. Th e anticodon base pai rs with the codon on mRNA.
The tRNA cloverl eaf三叶草结构has invariant不变的 and semi-invaria nt bases, and a conserved 保守的 set of base pair ing interactions .
Transfer RNA folds into a compact L-sh aped tertiary struc ture 三级结构with t he amino acid at on e end and the antic odon at the other e nd.
源自文库
Transcription generate s an RNA which is comp lementary to the DNA t emplate strand and has the same sequence as t he DNA coding strand. Translation reads each triplet of bases into one amino acid. Three turns of the DNA doubl e helix contain 30 bp, which cide for 10 amin o acids.
A space-filling model shows that tRNA terti ary structure is comp act紧密的. The two vi ews of tRNA are rotat ed by 90o. Photograph kindly provided by S. H. Kim.
Protein synthesis
Introduction
Coding region编码区 is a part of the gene that represents a protein sequence. Coding strand 编码链of DNA has the same sequen ce as mRNA. template strand模板链 of double-stranded DNA i s the one that is used to specify the sequence of a complementary single strand of RNA. (The non-template strand is identical in sequence t o the RNA product.) Transcription 转录is synthesis of RNA on a DNA template. Translation 翻译is synthesis of protein on the mRNA template.
A polyribosome多核糖体consists of an mRNA being translated simultaneously by several ribosomes m oving in the direction from 5’-3’ . Each ribos ome has two tRNA molecules, one carrying the nas cent amino acid初生氨基酸, the second carrying t he next amino acid to be added 添加氨基酸.
The meaning of tRNA is determined by it s anticodon and not by its amino acid.
Messenger RNA is t ranslated by ribos omes 核糖体
A ribosome consi sts of two subun its亚基.
Loop 环is a single-stranded region of a hairpin发夹 in R NA (or single-stranded DNA); corresponds to the sequen ce between inverted repeats 反向重复in duplex DNA.
Aminoacyl-tRNA synthetases are enzymes responsible for c ovalently linking amino acids to the 2′- or 3′-OH po sition of tRNA.
Anticodon反密码子 is a trinucleotide三核苷酸sequence in tRNA which is complementary to the codon in mRNA and e nables the tRNA to place the appropriate amino acid in response to the codon.
Transfer RNA is the adapte r
Aminoacyl氨酰-tRNA is transfer RNA carrying an amino aci d; the covalent 共价linkage is between the NH2 group o f the amino acid and either the 3′- or 2′-OH group o f the terminal base of the tRNA.
A tRNA has the dual properties of an ada ptor that recognizes both the amino acid and codon. The adeno sine腺苷at 3’ end i s covalently linked to an amino acid. Th e anticodon base pai rs with the codon on mRNA.
The tRNA cloverl eaf三叶草结构has invariant不变的 and semi-invaria nt bases, and a conserved 保守的 set of base pair ing interactions .
Transfer RNA folds into a compact L-sh aped tertiary struc ture 三级结构with t he amino acid at on e end and the antic odon at the other e nd.
源自文库
Transcription generate s an RNA which is comp lementary to the DNA t emplate strand and has the same sequence as t he DNA coding strand. Translation reads each triplet of bases into one amino acid. Three turns of the DNA doubl e helix contain 30 bp, which cide for 10 amin o acids.
A space-filling model shows that tRNA terti ary structure is comp act紧密的. The two vi ews of tRNA are rotat ed by 90o. Photograph kindly provided by S. H. Kim.