High-resolution NMR of an antisense DNA x RNA hybrid containing alternating chirally pure Rp methylphosphonates in the DNA backbone.
High-resolution NMR of an antisense DNA x RNA hybrid containing alternating chirally pure Rp methylphosphonates in the DNA backbone.
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DNA 主链中含有交替手性纯 Rp 甲基膦酸酯的反义 DNA x RNA 杂交体的高分辨率 NMR。
DOI：
10.1021/bi963008n
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发表时间：
1997
期刊：
影响因子：
2.9
通讯作者：
James,TL
中科院分区：
文献类型：
--
作者：
Mujeeb,A;Reynolds,MA;James,TL
A high-resolution proton NMR study has been performed on a hybrid duplex formed by a methylphosphonate (MP) oligodeoxyribonucleotide (MPO) and its target oligoribonucleotide, d(TMPCCMPTTMPAGMPCTMPCCMPTG)·r(CAGGAGCUAAGGA), where MP corresponds to positions of methylphosphonate linkages in the pureRpstereoconfiguration. MP-containing analogs of DNA are reported to be effective antisense agents capable of specifically inhibiting protein synthesis with theRpchiral MPOs exhibiting greater affinity for the target mRNA than theirSpcounterparts. Nearly complete proton resonance assignments of the hybrid duplex have been made using two-dimensional nuclear Overhauser effect (2D NOE) spectra, at three different mixing times, and double quantum-filtered COSY (2QF-COSY) spectra. The 2QF-COSY cross-peak patterns which are resolved have been analyzed qualitatively to suggest sugar conformations. Distance restraints have been obtained from the 2D NOE spectra of the duplex in D2O. These interproton distance restraints were determined using a complete relaxation matrix method to improve accuracy. Specifically, a new approach termed RANDMARDI has been utilized to calculate these distance restraints, accounting for spectral noise and errors in 2D NOE peak volume integration. The calculated interproton distances and sugar puckers have been analyzed to assess the solution conformation of the hybrid. The hybrid duplex appears to have an overall solution structure which is distinct from standard B- and A-forms, but the RNA strand exhibits features of the A-form. The absence of H1‘−H2‘ cross-peaks in the 2QF-COSY spectrum indicates a C3‘-endotype of conformation for ribose sugars in the RNA strand. The deoxyriboses in the antisense DNA strand exhibit a mixed behavior with almost equal scalar coupling constant values for H1‘−H2‘ and H1‘−H2‘ ‘ and a strong H3‘−H4‘ 2QF-COSY peak pattern. Variations in calculated values of interproton distances and sixth-rootRfactor analysis of experimental intensities indicate that the hybrid duplex may have a DNA strand with significant conformational plasticity.
