Please use this identifier to cite or link to this item:
Title: Synthesis and characterization of oligodeoxynucleotides containing O6-methyl-, O6-ethyl-, and O6-isopropylguanine
Authors: Li, B.F.L. 
Swann, P.F.
Issue Date: 1989
Citation: Li, B.F.L.,Swann, P.F. (1989). Synthesis and characterization of oligodeoxynucleotides containing O6-methyl-, O6-ethyl-, and O6-isopropylguanine. Biochemistry 28 (14) : 5779-5786. ScholarBank@NUS Repository.
Abstract: The carcinogenicity and mutagenicity of N-nitroso compounds is believed to result primarily from alkylation of DNA on O6 of guanine. To study the base-pairing properties of O6-alkylguanines and the structural changes produced in DNA by their presence, self-complementary dodecanucleotides were synthesized of the general structure CGCXAGCTYGCG (where X was O6-methylguanine, O6-ethylguanine, or O6-isopropylguanine and Y one of the natural bases). The O6-alkyldeoxyguanosines used as building blocks for the synthesis of the oligomers were prepared from the 6-(2-mesitylenesulfonyl) derivative by successive displacement with N-methylpyrrolidine and then alkoxide ions. The difficulties previously encountered in the synthesis of oligomers containing O6-alkylguanine [Borowsy-Borowski, H., & Chambers, R. W. (1987) Biochemistry 26, 2465-2471] were overcome by use of phenylacetyl as N2-protection for the O6-alkylguanine residue. The lability of the phenylacetyl group allowed very mild treatment with ammonia to be used for deprotection, and there was no detectable contamination of the product with 2,6-diaminopurine. Depurination of O6-alkylguanine residues with a free 5′-OH, which can occur if a protic acid is used to remove the 5′-protecting group from the alkylated nucleoside during oligonucleotide synthesis, was avoided by using ZnBr2. The oligonucleotide sequences that would form double helices containing O6-alkylG·C base pairs had lower optical melting temperatures (Tm) than the parent with G·C pairs, but only the isopropylG·C oligomer had significantly less hypochromicity. But the sequences giving helices with O6-alkylG·T base pairs had less hypochromicity than the parent and had biphasic melting profiles that began at a significantly lower temperature than the sequences with O6-alkylG·C base pairs. © 1989 American Chemical Society.
Source Title: Biochemistry
ISSN: 00062960
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

Page view(s)

checked on Jan 20, 2022

Google ScholarTM


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.