Amino acids genetic code identifying

A potentially general method of identifying a probe is, first, to purify a protein of interest by chromatography (qv) or electrophoresis. Then a partial amino acid sequence of the protein is deterrnined chemically (see Amino acids). The amino acid sequence is used to predict likely short DNA sequences which direct the synthesis of the protein sequence. Because the genetic code uses redundant codons to direct the synthesis of some amino acids, the predicted probe is unlikely to be unique. The least redundant sequence of 25—30 nucleotides is synthesized chemically as a mixture. The mixed probe is used to screen the Hbrary and the identified clones further screened, either with another probe reverse-translated from the known amino acid sequence or by directly sequencing the clones. Whereas not all recombinant clones encode the protein of interest, reiterative screening allows identification of the correct DNA recombinant. 

Consolidation of the results from many experiments permitted the assignment of 61 of the 64 possible codons. The other three were identified as termination codons, in part because they disrupted amino acid coding patterns when they occurred in a synthetic RNA polymer (Fig. 27-6). Meanings for all the triplet codons (tabulated in Fig. 27-7) were established by 1966 and have been verified in many different ways. The cracking of the genetic code is regarded as one of the most important scientific discoveries of the twentieth century. 

Fig. 10.1 (Continued), (b) Distribution of local optima in solution space for a basic amino acid dope (30% Arg, 30% Lys, 40% His). Due to die structure of die genetic code, a perfect soludon of fracdons of nucleotides for die given example does not exist. Instead, several islands of different suboptimal solutions are found. Seven local optima, marked by different colors (see die color version on die CD diat accompanies diis book), can be identified. Note diat die SOM uses toroidal boundaries, i.e., die left-most and right-most points lie close togedier, as do die top and bottom points.

The sequence of a protein can be determined using recombinant DNA technology to identify and sequence the piece of DNA encoding the protein. The amino acid sequence of the protein can then be deduced from its DNA sequence using the genetic code. 

Nirenberg Khorana and Ochoa Identified the genetic code words for amino acids. 

Natural variation in the genes that encode adrenergic receptors (ARs) have been identified. The variations of major interest for common diseases are those that occur with allele frequencies >1% and are termed polymorphisms. Within the coding region, polymorphic variation can result in either a change in the encoded amino acid (nonsynonymous) or, because of the redundancy of the genetic code, have no effect on the encoded residue (synonymous). The most common variants are single nucleotide polymorphisms (SNPs), but insertions and deletions are also found. AR polymorphisms have been considered as poten-... 

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