TY - JOUR
T1 - Effect of base composition on DNA bending by phosphate neutralization
AU - Strauss-Soukup, Juliane K.
AU - D. Rodrigues, Paula
AU - Maher, L. James
N1 - Funding Information:
We thank D. Eicher, C. Mountjoy, and M. Doerge for oligonucleotide synthesis, and A.M. Gacy and C.T. McMurray for assistance in thermal denaturation experiments. Supported by the Mayo Foundation, NIH grants GM47814 and GM54411 to L.J.M., a University of Nebraska Medical Center Regents Fellowship to J.K.S.-S., and an NIH predoctoral training fellowship to P.D.R. Author L.J.M. is a Harold W. Siebens Research Scholar.
PY - 1998/6/9
Y1 - 1998/6/9
N2 - Of the many forces involved in DNA bending by proteins, we have focused on the possible role of asymmetric phosphate neutralization due to interactions between the negatively charged phosphate backbone of duplex DNA and cationic amino acids of an approaching protein. The resulting unbalanced charge distribution along the duplex DNA is thought to induce the double helix to collapse toward the neutralized surface. Previous work has confirmed that DNA bending (~ 20.7 ± 4°) is induced by asymmetric incorporation of six uncharged racemic methylphosphonate analogs partially neutralizing one face of GC-rich duplex DNA. We have now analyzed DNA duplexes with similar patches of methylphosphonate linkages in an AT-rich sequence context and again observe bending toward the neutralized face, to an extent (20 ± 0.6°) comparable to that observed for neutral patches in GC-rich DNA. The similar induced bend angles in AT-rich and GC-rich contexts does not reveal increased flexibility in AT-rich sequences, or a particular propensity of A-T base pairs to roll toward the minor groove in the tested sequences.
AB - Of the many forces involved in DNA bending by proteins, we have focused on the possible role of asymmetric phosphate neutralization due to interactions between the negatively charged phosphate backbone of duplex DNA and cationic amino acids of an approaching protein. The resulting unbalanced charge distribution along the duplex DNA is thought to induce the double helix to collapse toward the neutralized surface. Previous work has confirmed that DNA bending (~ 20.7 ± 4°) is induced by asymmetric incorporation of six uncharged racemic methylphosphonate analogs partially neutralizing one face of GC-rich duplex DNA. We have now analyzed DNA duplexes with similar patches of methylphosphonate linkages in an AT-rich sequence context and again observe bending toward the neutralized face, to an extent (20 ± 0.6°) comparable to that observed for neutral patches in GC-rich DNA. The similar induced bend angles in AT-rich and GC-rich contexts does not reveal increased flexibility in AT-rich sequences, or a particular propensity of A-T base pairs to roll toward the minor groove in the tested sequences.
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U2 - 10.1016/S0301-4622(98)00112-4
DO - 10.1016/S0301-4622(98)00112-4
M3 - Article
C2 - 9691271
AN - SCOPUS:0032499763
VL - 72
SP - 297
EP - 306
JO - Biophysical Chemistry
JF - Biophysical Chemistry
SN - 0301-4622
IS - 3
ER -