1、CHAPTER 15,The Genetic Code,Deciphering,Cell-free translation of artificial RNAs (Nirinberg,1961),The triplet binding assay (Nirinberg,1964) tRNA和氨基酸、核糖體及三聯(lián)體的結(jié)合是特異的 上述結(jié)合的復(fù)合體大分子是不能通過硝酸纖維濾膜的微孔，而tRNA- 氨基酸的復(fù)合體是可以通過的。,poly(U) -UUU- polyphenylalanine poly(C) -CCC- polyproline poly(A) -AAA- polylysine poly

2、(G) - did not work because of the complex secondary structure,Attempt to Decipher: 1954, George Gamow,Three rules govern the genetic code,Features:,The code is degenerate Wobble in the anticodon The code is nearly universal,Suppressor mutations can reside in the same or a different gene,The first ru

3、le holds that codons are read in a 5 to 3 direction. The second rule is that codons are nonoverlapping and the message contains no gaps. The final rule is that the message is translated in a fixed reading frame, which is set by the initiation codon.,Three rules govern the genetic code,Features:,The

4、code is degenerate Wobble in the anticodon The code is nearly universal,Suppressor mutations can reside in the same or a different gene,degeneracy,Many amino acides are specified by more than one codon, the phenomenon called degeneracy.,Wobble,Wobble concept The base at the 5 end of the anticodon is

5、 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 table,Universality,The standard codons are true for most organisms, but not for all.,硒代半胱氨酸：UGA 識別：發(fā)夾結(jié)構(gòu)和硒代半胱氨酸特異的翻譯延伸因子,Codon Preference,Three rules govern the genetic code,Features:,The code is degenerate Wobble in the anticodon The code