Assignment of phosphorus-31 and nonexchangeable proton resonances in a symmetrical 14 base pair lac pseudooperator DNA fragment
The /sup 31/P chemical shifts of all 13 phosphates and the chemical shifts of nearly all of the nonexchangeable protons of a symmetrical 14 base pair lac pseudooperator DNA fragment have been assigned by regiospecific labeling with oxygen-17 and two-dimensional NMR techniques. At 22 /sup 0/C, 8 of the 13 phosphorus resonances can distinctly be resolved while the remaining 5 resonances occur in two separate overlapping regions. The /sup 31/P chemical shifts of this particular 14 base pair oligonucleotide do not follow the general observation that the more internal phosphate is located within the oligonucleotide sequence the more upfield the /sup 31/P resonance occurs, as shown from other /sup 31/P assignment studies. Failure of this general rule is believed to be a result of helical distortions that occur along the oligonucleotide double helix, on the basis of the analysis of Callidine. Notable exceptions to the phosphate position relationship are 5'-Py-Pu-3' dinucleotide sequences, which resonate at the lower field strength than expected in agreement with similar results as reported by Ott and Eckstein. The most unusual /sup 31/P resonance occurs most upfield in the /sup 31/P spectrum, which has been assigned to the second phosphate position (5'-GpT-3') from the 5' end. This unusual chemical shift may be the result of the predicted large helical twist angle that occurs at this position in the 14-mer sequence. Assignments of proton resonances were made from two-dimensional /sup 1/H-/sup 1/H nuclear Overhauser effect (NOESY) connectivities in a sequential manner applicable to right-handed B-DNA, in conjunction with two-dimensional homonuclear and heteronuclear J-correlated spectroscopies (/sup 1/H-/sup 1/H COSY and /sup 31/P-/sup 1/H HETCOR). Most nonexchangeable base proton and deoxyribose proton (except for some unresolved H4', H5', and H5'' protons) resonances were assigned.
- Research Organization:
- Purdue Univ., West Lafayette, IN
- OSTI ID:
- 5876674
- Journal Information:
- Biochemistry; (United States), Vol. 26:13
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DNA
NUCLEAR MAGNETIC RESONANCE
GENE OPERONS
GENE REGULATION
CHEMICAL SHIFT
OXYGEN 17
PHOSPHORUS 31
PROTONS
BARYONS
ELEMENTARY PARTICLES
EVEN-ODD NUCLEI
FERMIONS
HADRONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEI
NUCLEIC ACIDS
NUCLEONS
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
OXYGEN ISOTOPES
PHOSPHORUS ISOTOPES
RESONANCE
STABLE ISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics