TY  - JOUR
A1  - Kincaid, Kristi
A1  - Beckman, Jeff
A1  - Zivkovic, Aleksandra
A1  - Halcomb, Randall L.
A1  - Engels, Joachim W.
A1  - Kuchta, Robert D.
T1  - Exploration of factors driving incorporation of unnatural dNTPS into DNA by Klenow fragment (DNA polymerase I) and DNA polymerase {alpha}
T2  - Nucleic acids research
N2  - In order to further understand how DNA polymerases discriminate against incorrect dNTPs, we synthesized two sets of dNTP analogues and tested them as substrates for DNA polymerase a (pol alpha) and Klenow fragment (exo-) of DNA polymerase I (Escherichia coli ). One set of analogues was designed to test the importance of the electronic nature of the base. The bases consisted of a benzimidazole ring with one or two exocyclic substituent(s) that are either electron-donating (methyl and methoxy) or electronwithdrawing (trifluoromethyl and dinitro). Both pol a and Klenow fragment exhibit a remarkable inability to discriminate against these analogues as compared to their ability to discriminate against incorrect natural dNTPs. Neither polymerase shows any distinct electronic or steric preferences for analogue incorporation. The other set of analogues, designed to examine the importance of hydrophobicity in dNTP incorporation, consists of a set of four regioisomers of trifluoromethyl benzimidazole. Whereas pol a and Klenow fragment exhibited minimal discrimination against the 5- and 6-regioisomers, they discriminated much more effectively against the 4- and 7-regioisomers. Since all four of these analogues will have similar hydrophobicity and stacking ability, these data indicate that hydrophobicity and stacking ability alone cannot account for the inability of pol a and Klenow fragment to discriminate against unnatural bases. After incorporation, however, both sets of analogues were not efficiently elongated. These results suggest that factors other than hydrophobicity, sterics and electronics govern the incorporation of dNTPs into DNA by pol {alpha} and Klenow fragment.
Y1  - 2006
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2815
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30-25925
SN  - 1362-4962
SN  - 0305-1048
N1  - (c) The Author 2005. Published by Oxford University Press. All rights reserved.
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VL  - 33
IS  - 8
SP  - 2620
EP  - 2628
PB  - Oxford Univ. Press
CY  - Oxford
ER  -