Conformational analysis of a ribopentanucleoside tetraphosphate in aqueous solution. A two-dimensional NMR study at 500 MHz.

AUTOR(ES)

Lankhorst, P P

RESUMO

The 30 ribose proton resonances of the pentaribonucleoside tetraphosphate m6(2)AUm6(2)AUm6(2)A have been assigned unequivocally by means of spin-echo-correlated spectroscopy, 2D J-resolved spectroscopy and Nuclear Overhauser difference spectroscopy, carried out at 500 MHz. A detailed comparison of the conformational properties of the title compound with its constituent fragments m6(2)AUm6(2)AU, m6(2)AUm6(2)A, m6(2)AU and the relevant monomers is given. Chemical shift data indicate the existence of a doubly "bulged out" conformer, in which the two interior U-fragments are not involved in regular nearest neighbour stacking interactions. The coupling constants of the ribose-ring are interpreted in terms of the N/S equilibrium, and population distributions along the backbone angles beta and gamma are presented. The combined data suggest a strong similarity between the 5'-terminal triplets in m6(2)AUm6(2)AUm6(2)A, m6(2)AUm6(2)AU and m6(2)AUm6(2)A2.

Documentos Relacionados

• Conformational characteristics of the hexanucleoside pentaphosphate AUAUAU: a 2D NMR study at 500 MHz.
• Conformational analysis of a modified ribotetranucleoside triphosphate: m6(2)A-U-m6(2)A-U studied in aqueous solution by nuclear magnetic resonance at 500 MHz.
• Conformational analysis of r(CGCGCG) in aqueous solution: an A-type double helical conformation studied by two-dimensional nuclear Overhauser effect spectroscopy.
• A one- and two-dimensional NMR study of the B to Z transition of (m5dC-dG)3 in methanolic solution.
• Influence of uracil defect on DNA structure: 1H NMR investigation at 500 MHz.