Adenine base triplet

The sequence of bases on the mRNA specifies the polypeptide to be synthesized. Each sequence of three consecutive bases (base triplet) comprises a codon which codes or specifies for a particular tRNA which carries a particular amino acid. The codon is written using the one-letter symbols for the bases, e.g., ACC designates the codon with the base sequence adenine-cytosine-cytosine. 

The hydrogen bonds are employed by the nucleobases to form base pairs interactions. It is known that there are 28 possible base-pairing motifs that involve at least two hydrogen bonds, which can be formed between the four common nucleobases. These include reverse Watson-Crick, (Fig. 3a), Hoogs-teen and Wobble base pairs (Fig. 3b), and base-triplets (Fig. 3c). In the case of adenine and guanine larger aggregates are also possible. 

The genetic code is composed of four letters —two pyrimidine nitrogenous bases, thymine and cytosine, and two purine bases, guanine and adenine—which can be regarded functionally as arranged in codons (or triplets). Each codon consists of a combination of three letters therefore, 43 (64) different codons are possible. Sixty-one codons code for specific amino acids (three produce stop signals), and as only 20 different amino acids are used to make proteins, one amino acid can be specified by more than one codon. 

Abbreviations used for purine and pyrimidine bases on ribonucleotides U, uridine C, cytosine A, adenine G, guanine. Stop och) refers to the ochre termination triplet, Stop (amb) refers to the amber termination triplet, and Stop (opal) refers to the opal termination triplet. 

An overview of protein synthesis is shown in Fig. S.A12. The linear sequence in mRNA that is translated to protein contains four bases, adenine, uracil, guanine and cytosine. The four letters A,U,G and C constitute the mRNA alphabet . This basic alphabet is used in triplets of bases called codons. The codons on mRNA pair up with anticodon or complementary triplets on the tRNA, thus matching the mRNA code to an amino-acid sequence. 

The code is made up of adenine (A), thymine (T), guanine (G), and cytosine (C), the nucleotide bases of DNA. Each gene s code combines them in various ways to spell out three-letter triplets (codons) that specify which amino acid is needed at each step in making a protein. 

Fig. 22. The complexation induced shifts of the energies of the lowest excitations of nucleic acid bases in the dimers. Shifts are calculated with respect to the free molecule (guanine or cytosine in the guanine-cytosine complex and adenine or thymine in the adenine-thymine complex). For each monomer four excitations are given singlet-singlet A , singlet-singlet A , singlet-triplet A , and singlet-triplet A . Data taken from [Wesolowski, J. Am. Chem. Soc., 126, (2004) 11444].

The genetic code incorporated in the DNA molecule consists of pairs of bases arranged in triplets. The bases utilized are the purine bases adenine (A) and guanine (G), and the pyrimidine bases, thymine (T) and cytosine (C). The basic mechanism of the... 

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