We have found that an activated derivative of guanylic acid in which the phosphate group is converted to a 2-Me Imidazole derivative (2-MeImpG) undergoes very efficient regiospecific polymerization on a poly(C) template to give natural 3'-5'-linked oligoguanylic acids with chain lengths up to 30 or higher. Furthermore, templates containing C and one or more additional bases direct the synthesis of complementary oligomers. CCGCC for example directs the synthesis of GGCGG in up to 20% yield and from 2-MeImpG and 2-MeImpC. We plan to extend these studies with the intention of developing an RNA polymerase model that will enable us to use as wide a range of oligomers as possible as templates to direct complementary synthesis. Our long range goal is the development of a non-enzymatic replicating system. In addition to these extensions of our previous work, we hope to initiate four new areas of research:- (1) We will attach polycations such as oligoarginine to the 3'-terminus of templates in such a way as to force the correct initiation of synthesis. (2) We will use short oligonucleotide initiators to analyze the effect of different steps in the reaction on overall rates and efficiencies of the reactions. (3) We will use """"""""sliding"""""""" to bring about template synthesis on oligomers with a repeating sequence. If we are successful, it will be possible to achieve template-directed synthesis on a double-helical template, without needing to separate the strands. (4) We will investigate peptide catalysts of the template-directed reactions of dGTP.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM013435-23
Application #
3268492
Study Section
Bio-Organic and Natural Products Chemistry Study Section (BNP)
Project Start
1978-12-01
Project End
1992-06-30
Budget Start
1990-07-01
Budget End
1992-06-30
Support Year
23
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Salk Institute for Biological Studies
Department
Type
DUNS #
005436803
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Hill Jr, A R; Kumar, S; Patil, V D et al. (1991) Which 3-ribofuranosyl-substituted purine 5'-phosphates undergo template-directed oligomerization? J Mol Evol 32:447-53
Rodriguez, L; Orgel, L E (1991) Pyrophosphate formation as the most efficient condensation reaction of activated nucleotides. J Mol Evol 32:101-4
Rodriguez, L; Orgel, L E (1991) Template-directed extension of a guanosine 5'-phosphate covalently attached to an oligodeoxycytidylate template. J Mol Evol 33:477-82
Rodriguez, L; Orgel, L E (1991) Acceleration of the template-directed reactions of nucleoside 5'-phosphorimidazolides by acylation. J Mol Evol 32:278-81
Hill Jr, A R; Orgel, L E (1991) Photooxidation of oligodeoxynucleotides by UO2(2+). Bioconjug Chem 2:431-4
Ng, K E; Orgel, L E (1989) Reaction on alternating GC oligonucleotide templates. J Mol Evol 29:101-7
Orgel, L E (1989) The origin of polynucleotide-directed protein synthesis. J Mol Evol 29:465-74
Ng, K M; Orgel, L E (1989) Replacement of the 3'-CH group by nitrogen in the carbocyclic analogue of thymidine. J Med Chem 32:1754-7
Hill Jr, A R; Kumar, S; Leonard, N J et al. (1988) Template-directed oligomerization of 3-isoadenosine 5'-phosphate. J Mol Evol 27:91-5
Ng, K E; Orgel, L E (1987) The action of a water-soluble carbodiimide on adenosine-5'-polyphosphates. Nucleic Acids Res 15:3573-80

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