1AFZ

SOLUTION NMR STRUCTURE OF AN 11 BASE-PAIR OLIGONUCLEOTIDE FROM THE HUMAN N-RAS PROTOONCOGENE ENCODING FOR AMINO ACIDS 11-13 OF P21, MINIMIZED AVERAGE STRUCTURE

Summary for 1AFZ

• Entry DOI: 10.2210/pdb1afz/pdb
• Related: 1AF1
• Descriptor: DNA (5'-D(*GP*GP*CP*AP*GP*GP*TP*GP*GP*TP*G)-3'), DNA (5'-D(*CP*AP*CP*CP*AP*CP*CP*TP*GP*CP*C)-3') (2 entities in total)
• Functional Keywords: dna duplex, human n-ras gene, codon 12 sequence, deoxyribonucleic acid, dna
• Total number of polymer chains: 2
• Total formula weight: 6709.38

Authors

Zegar, I.S.,Stone, M.P. (deposition date: 1997-03-18, release date: 1997-08-20, Last modification date: 2024-05-22)

Primary citation

Zegar, I.S.,Stone, M.P.
Solution structure of an oligodeoxynucleotide containing the human N-ras codon 12 sequence refined from 1H NMR using molecular dynamics restrained by nuclear Overhauser effects.
Chem.Res.Toxicol., 9:114-125, 1996

PubMed Abstract: The structure of d(GGCAGGTGGTG).d(CACCACCTGCC), consisting of codons 11, 12 (underlined), and 13 of the human n-ras protooncogene, was refined from 1H NMR data. Patterns of internucleotide NOEs consistent with a B-form helix were observed for each strand. NOE intensities between purine H8 and H1' protons were small compared to intensities between cytosine H5 and H6 protons, indicative of glycosyl torsion angles in the anti range. Cross-peaks were observed between purine H8 and pyrimidine H5 and CH3 protons on adjacent bases in the direction of purine (5'-->3')pyrimidine, but not in the direction pyrimidine(5'-->3')purine. Watson-Crick hydrogen bonding between bases was intact. A total of 232 experimental distance restraints were obtained. Of these, 143 were intra-residue restraints and 89 were inter-residue restraints. A restrained molecular dynamics/simulated annealing approach yielded 6 MD structures calculated from a B-form starting structure and 6 MD structures from an A-form starting structure. These refined to an average pairwise rms difference of 0.92 angstrom, with maximum pairwise rmsd of 1.35 angstroms. Accuracy of emergent structures was assessed by relaxation matrix back-calculation. The sixth-root residual index of 7.0 x 10(-2) measured between the refined structures and the NOE intensity data suggested that the former were in reasonable agreement with the NOE data. The refined solution structures were in the B-family. Similar to the human n-ras codon 61 sequence [Feng, B., & Stone, M.P. (1995) Chem. Res. Toxicol. 8, 821-832], the ras12 sequence contained local variations in B-like conformation which did not confer large structural alterations upon the duplex, but perhaps modulated the reactivity of the first as compared to the second guanine in codon 12.

PubMed: 8924579
DOI: 10.1021/tx9500787

Experimental method

SOLUTION NMR