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1、CHAPTER 15The Genetic CodeDeciphering Cell-free translation of artificial RNAs (Nirinberg,1961)The triplet binding assay (Nirinberg,1964) tRNAtRNA和氨基酸、核糖体及三联体的结合是特异的和氨基酸、核糖体及三联体的结合是特异的 上述结合的复合体大分子是不能通过硝酸纤维滤膜的微孔，而上述结合的复合体大分子是不能通过硝酸纤维滤膜的微孔，而tRNA- tRNA- 氨基氨基酸的复合体是可以通过的。酸的复合体是可以通过的。 poly(U) -UUU- polyph
2、enylalaninepoly(C) -CCC- polyprolinepoly(A) -AAA- polylysinepoly(G) - did not work because of the complex secondary structureAttempt to Decipher: 1954, George Gamow Three rules govern the genetic codeFeatures:The code is degenerate Wobble in the anticodonThe code is nearly universalThe code is nearl
3、y universalSuppressor mutations can reside in the same or a different genenThe first rule holds that codons are read in a 5 to 3 direction.nThe second rule is that codons are nonoverlapping and the message contains no gaps.nThe final rule is that the message is translated in a fixed reading frame, w
4、hich is set by the initiation codon.Three rules govern the genetic codeFeatures:The code is degenerate Wobble in the anticodonThe code is nearly universalThe code is nearly universalSuppressor mutations can reside in the same or a different genedegeneracyMany amino acides are specified by more than
5、one codon, the phenomenon called degeneracy.WobblenWobble conceptnThe base at the 5 end of the anticodon is no as spatically confined as the other two allowing it to form hydrogen bonds with any of several based located at the 3 end of a codon, with pairing restrict to those on the right tableUniver
6、salityThe standard codons are true for most organisms, but not for all. 硒代半胱氨酸：硒代半胱氨酸：UGA UGA 识别：发夹结构和硒代半胱氨酸识别：发夹结构和硒代半胱氨酸特异的翻译延伸因子特异的翻译延伸因子Codon PreferenceThree rules govern the genetic codeFeatures:The code is degenerate Wobble in the anticodonThe code is nearly universalThe code is nearly universalSuppressor mutations can reside in the same or a different gene
