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Sequence composition effects on the stabilities of triple helix formation by oligonucleotides containing N7-deoxyguanosine

Brunar, Helmut and Dervan, Peter B. (1996) Sequence composition effects on the stabilities of triple helix formation by oligonucleotides containing N7-deoxyguanosine. Nucleic Acids Research, 24 (11). pp. 1987-1991. ISSN 0305-1048. PMCID PMC145894.

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A nonnatural nucleoside, 7-(2-deoxy-β-D-erythro-pento-furanosyl)- guanine (d7G), mimics protonated cytosine and specifically binds GC base pairs within a pyrimidine - purine - pyrimidine triple helix. The differences in association constants (KT) determined by quantitative footprint titration experiments at neutral pH reveal dramatic sequence composition effects on the energetics of triple helix formation by oligonucleotides containing d7G. Purine tracts of sequence composition 5'-d(AAAAAGAGAGAGAGA)-3' are bound by oligonucleotide 5'- d(TTTTT7GT7GT7GT7GT7GT)-3' three orders of magnitude less strongly than by 5'-d(TTTTTmCTmCTmCTmCTmCT)-3' (KT = 1.5 x 10(6) M(-1) and KT > or = 3 x 10(9) M(-1) respectively). Conversely, purine tracts of sequence composition 5'-d(AAAAGAAAAGGGGGGA)-3' are bound by oligonucleotide 5'- d(TTTTmCTTTT7G7G7G7G7G7GT)-3' five orders of magnitude more strongly than by 5'-d(TTTTmCTTTTmCmCmCmCmCT)-3' (KT > or = 3 x 10(9) M(-1) and KT < 5 x 10(4) M(-1) respectively). The complementary nature of d7G and mC expands the repertoire of G-rich sequences which may be targeted by triple helix formation.

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Additional Information:© 1996 Oxford University Press. Received March 25, 1996; Accepted April 13, 1996. We are grateful to the Office of Naval Research for support and to the Austrian Science Foundation for an Erwin Schrödinger Postdoctoral Fellowship to H.B.
Funding AgencyGrant Number
Office of Naval Research (ONR)UNSPECIFIED
FWF Der WissenschaftsfondsUNSPECIFIED
PubMed Central ID:PMC145894
Record Number:CaltechAUTHORS:BRUnar96
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Official Citation:Helmut Brunar and Peter B. Dervan Sequence Composition Effects on the Stabilities of Triple Helix Formation By Oligonucleotides Containing N7-deoxyguanosine Nucl. Acids Res. (1996) 24 (11): 1987-1991 doi:10.1093/nar/24.11.1987
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13757
Deposited By: Tony Diaz
Deposited On:10 Jul 2009 16:35
Last Modified:09 May 2016 19:29

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