Total synthesis of the structural gene for the precursor of a tyrosine suppressor transfer RNA from Escherichia coli. 4. Synthesis of deoxyribopolynucleotide segments corresponding to the nucleotide sequence 47-78.

The chemical syntheses of the dodecanucleotide, d(G-C-C-G-C-T-C-G-G-G-A-A), the decanucleotides, d(T-T-T-A-G-A-G-T-C-T), d(G-C-T-C-C-C-T-T-T-G), d(C-G-G-C-C-A-A-A-G-G), and the nonanucleotide, d(G-A-G-C-A-G-A-C-T), are described. The deoxypolynucleotides together represent the DNA duplex corresponding to the nucleotide sequence 47-78 of the gene for the tyrosine suppressor tRNA. Chemical syntheses used protected mono- and oligonucleotides and stepwise condensation methods. The detailed plans used are given in Diagrams 1 to 4 in the text. Two additional notable features in the present syntheses were: (a) solvent extraction procedures for the preparation of oligonucleotides as large as pentanucleotides and (b) the demonstration that a heptanucleotide containing 5'-phosphate group can be used successfully in condensation with the 3'-OH group of another oligonucleotide. The synthetic polynucleotides were purified and characterized at protected and unprotected levels.