Biomedical subjects

H Büchi

Publications and source records attributed to H Büchi.

10 recordsLinked to original sources

PubMed1976

Total synthesis of the structural gene for the precursor of a tyrosine suppressor transfer RNA from Escherichia coli. 11. Enzymatic joining to form the total DNA duplex.

The DNA duplex corresponding to the entire length (126 nucleotides) of the precursor for an Escherichia coli tyrosine tRNA has been synthesized. Duplex [I] (Sekiya, T., Besmer, P., Takeya, T., and Khorana, H. G.(1976) J. Biol. Chem. 251, 634-641), corresponding to the nucleotide sequence 1-26, containing single-stranded ends and carrying one appropriately labeled 5'-phosphate group, was joined to duplex [II] (Loewen, P. C., Miller, R. C., Panet, A., Sekiya, T., and Khorana, H. G. (1976) J. Biol. Chem. 251, 642-650) (nucleotide sequence 23-66 or 23-60) was phosphorylated with [gamma-33P]ATP at the 5'-OH ends. Duplex [III] (Panet, A., Kleppe, R., Kleppe, K., and Khorana, H. G. (1976) J. Biol. Chem. 251, 651-657) (nucleotide sequence 57-94 (Fig. 2)) was also phosphorylated at 5'-ends with [gamma-33P]ATP and was joined to duplex [IV] (Caruthers, M. H., Kleppe, R., Kleppe, K., and Khorana, H. G. (1976) J. Biol. Chem. 251, 658-666) (nucleotide sequence 90-126) which carried a 33P-labeled phosphate group on nucleotide 90. The joined product, duplex [III + IV] (nucleotide sequence 57-126) was characterized. The latter duplex was joined to the duplex [I + II] to give the total duplex. The latter contains singlestranded ends (nucleotides 1 to 6 and 121 to 126) which can either be "filled in" to produce the completely base-paired duplex or may be used to add the promoter and terminator regions at the appropriate ends.

Base Sequence↗

PubMed1976

Total synthesis of the structural gene for the precursor of a tyrosine suppressor transfer RNA from Escherichia coli. 1. General introduction.

With the ultimate objective of the total synthesis of a tRNA gene including its transcriptional signals, an Escherichia coli tyrosine suppressor tRNA gene was chosen. The arguments in favor of this choice are presented. A plan for the total synthesis of the 126-nucleotide-long DNA duplex corresponding to a precursor (Altman S., and Smith, J. D. (1971) Nature New Biol. 233, 35) to the above tRNA is formulated. The plan involves: (a) the chemical synthesis of 26 deoxyribooligonucleotide segments, (b) polynucleotide ligase-catalyzed joining of several segments at a time to form a total of four DNA duplexes with appropriate comlementary single-stranded ends, and (c) the joining of the duplexes to form the entire DNA duplex. Ten accompanying papers describe the experimental realization of this objective.

Base Sequence↗

PubMed1976

Total synthesis of the structural gene for the precursor of a tyrosine suppressor transfer RNA from Escherichia coli. 6. Synthesis of the deoxyribopolynucleotide segments corresponding to the nucleotide sequence 100-126.

Chemical syntheses of the tridecanucleotide, d(G-C-T-T-C-C-C-G-A-T-A-A-G), the dodecanucleotide, d(G-C-T-C-C-C-T-T-A-T-C-G), the decanucleotide, d(G-G-A-G-C-A-G-G-C-C), the nonanucleotide, d(T-A-C-T-G-G-C-C-T), and the hexanucleotide, d(G-G-A-A-G-C), are described. Together, these syntheses represent the nucleotide sequence 100-126 of the DNA corresponding to the Escherichia coli tyrosine tRNA precursor. The synthesis of the dodecanucleotide d(G-C-T-C-C-C-T-T-A-T-C-G), was accomplished by the condensation of the previously described protected nonanucleotide, d[(MeOTr)ibG-anC-T-anC-anC-anC-T-T-bzA], with the trinucleotide block d[pT-anC-mbG(Ac)]. Synthesis of the other segments involved stepwise condensations to the 3'-OH group of growing oligonucleotide chains, starting with suitably protected deoxyribonucleosides and using protected mono-, di-, and trinucleotides as the incoming blocks. The final products, after deprotection, were purified by anion exchange chromatography and characterized. The synthesis of this part of the DNA was planned so that only a hexanucleotide segment is used to go up to the 3'-end (nucleotide 126) of the DNA and, therefore, it is amenable to elongation by chemical methods when the nucleotide sequence of the several nucleotides beyond this end becomes known.

Base Sequence↗

PubMed1972