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 http://resolver.caltech.edu/CaltechAUTHORS:BRUnar96
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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.
|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.|
|Subject Keywords:||DNA; PH; 2'-O-METHYLPSEUDOISOCYTIDINE; RECOGNITION; TITRATION; CLEAVAGE; CYTOSINE; BINDING; RANGE|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||10 Jul 2009 16:35|
|Last Modified:||26 Dec 2012 10:54|
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