期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：23
页码：7166-7170
DOI：10.1073/pnas.79.23.7166
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We have constructed primed phi X174 DNA templates containing either acetylated or deacetylated aminofluorene adducts at the C-8 position of guanine. T4 DNA polymerase terminates synthesis one nucleotide before the acetylated adducts but incorporates an additional nucleotide opposite the deacetylated guanylaminofluorene. These observations can be explained by the known preferred conformations of the acetylated and deacetylated guanosinylaminofluorene nucleosides--the former favoring the syn conformation (so that in DNA the guanine is displaced from the helix by the fluorene ring) and the latter preferring the anti conformation (which allows normal base pairing of the guanine with cytosine). A similar differentiation between the two adducts was found with Escherichia coli DNA polymerase I. In contrast, avian myeloblastosis virus (AMV) reverse transcriptase, which terminated with a nucleotide inserted opposite the acetylated adducts, was less able to do so at the deacetylated adducts. The nucleoside incorporated by AMV reverse transcriptase opposite the acetylated adduct was exclusively cytidine, which suggests regular base pairing with the reacted guanosine nucleoside in the anti conformation; however, synthesis was completely blocked and unable to continue beyond this point. The differences between the termination patterns of the prokaryotic enzymes and AMV reverse transcriptase indicates that specific properties of a replicating polymerase can influence the conformation of a reacted nucleoside in the DNA, thus altering its recognition and possibly its mutagenic activity.
