Abstract
The structure of the cytosine-adenine mispair in a 7 base pair duplex has been investigated by proton NMR spectroscopy. At low pH, the predominant structure is protonated on the A residue and assumes a wobble conformation consistent with previous findings. The C residue of the mispair is found in a C2′-C3′ endo eqilibrium. This is confirmed by molecular dynamics calculations which suggest that the conformation of the protonated wobble is flexible and not as rigid as a normal base pair. As the solution pH is raised, a structural transition is observed with an apparent pK of 7.54 at 23°C. At higher pH the predominant structure is one in which both the C and A residues are intrahelical. Evidence is presented that this structure corresponds to a reverse wobble in which the two bases are held together by one hydrogen bond. This structure is much less stable than the protonated form and even at low temperature single strands are observed in slow exchange with the neutral duplex form.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1933-1941 |
| Number of pages | 9 |
| Journal | Nucleic Acids Research |
| Volume | 20 |
| Issue number | 8 |
| State | Published - 1992 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Genetics
- Statistics, Probability and Uncertainty
- Applied Mathematics
- Health, Toxicology and Mutagenesis
- Toxicology
- Genetics(clinical)
Cite this
The pH dependent configurations of the C.A mispair in DMA. / Boulard, Y.; Cognet, J. A H; Gabarro-Arpa, J.; Le Bret, M.; Sowers, Lawrence; Fazakerley, G. V.
In: Nucleic Acids Research, Vol. 20, No. 8, 1992, p. 1933-1941.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The pH dependent configurations of the C.A mispair in DMA
AU - Boulard, Y.
AU - Cognet, J. A H
AU - Gabarro-Arpa, J.
AU - Le Bret, M.
AU - Sowers, Lawrence
AU - Fazakerley, G. V.
PY - 1992
Y1 - 1992
N2 - The structure of the cytosine-adenine mispair in a 7 base pair duplex has been investigated by proton NMR spectroscopy. At low pH, the predominant structure is protonated on the A residue and assumes a wobble conformation consistent with previous findings. The C residue of the mispair is found in a C2′-C3′ endo eqilibrium. This is confirmed by molecular dynamics calculations which suggest that the conformation of the protonated wobble is flexible and not as rigid as a normal base pair. As the solution pH is raised, a structural transition is observed with an apparent pK of 7.54 at 23°C. At higher pH the predominant structure is one in which both the C and A residues are intrahelical. Evidence is presented that this structure corresponds to a reverse wobble in which the two bases are held together by one hydrogen bond. This structure is much less stable than the protonated form and even at low temperature single strands are observed in slow exchange with the neutral duplex form.
AB - The structure of the cytosine-adenine mispair in a 7 base pair duplex has been investigated by proton NMR spectroscopy. At low pH, the predominant structure is protonated on the A residue and assumes a wobble conformation consistent with previous findings. The C residue of the mispair is found in a C2′-C3′ endo eqilibrium. This is confirmed by molecular dynamics calculations which suggest that the conformation of the protonated wobble is flexible and not as rigid as a normal base pair. As the solution pH is raised, a structural transition is observed with an apparent pK of 7.54 at 23°C. At higher pH the predominant structure is one in which both the C and A residues are intrahelical. Evidence is presented that this structure corresponds to a reverse wobble in which the two bases are held together by one hydrogen bond. This structure is much less stable than the protonated form and even at low temperature single strands are observed in slow exchange with the neutral duplex form.
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UR - http://www.scopus.com/inward/citedby.url?scp=0026582206&partnerID=8YFLogxK
M3 - Article
VL - 20
SP - 1933
EP - 1941
JO - Nucleic Acids Research
JF - Nucleic Acids Research
SN - 0305-1048
IS - 8
ER -