Indirect NMR Spin-Spin Coupling Constants 3J(P,C) and 2J(P,H) across the P-O···H-C Link Can Be Used for Structure Determination of Nucleic Acids
详细信息 查看全文
- 作者：Vladimí ; r Sychrovsk<img src="http ; //pubs.acs.org/images/entities/yacute.gif" border="0"> ; Ji<img src="http ; //pubs.acs.org/images/entities/rcaron.gif" border="0">í ; <img src="http ; //pubs.ac
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：May 31, 2006
- 年：2006
- 卷：128
- 期：21
- 页码：6823 - 6828
- 全文大小：214K
- 年卷期：v.128,no.21(May 31, 2006)
- ISSN：1520-5126
文摘
Calculated indirect NMR spin-spin coupling constants 3J(P,C) and 2J(P,H) were correlated withthe local structure of the P-O···H-C linkage between the nucleic acid (NA) backbone phosphate and theH-C group(s) of a nucleic acid base. The calculations were carried out for selected nucleotides from thelarge ribosomal subunit (Ban et al. Science 2000, 289, 905) with the aim of identifying NMR parameterssuitable for detection of certain noncanonical RNA structures. As calculations in the model system, dimethyl-phosphate-guanine, suggest, the calculated indirect spin-spin couplings across the linkage are sensitiveto the mutual orientation and distance between the phosphate and nucleic acid base. A short distancebetween the nucleic acid base and phosphate group and the angles C···P-O and P···C-H smaller than50<IMG SRC="/images/entities/deg.gif"> are prerequisites for a measurable spin-spin interaction of either coupling (
J > 1 Hz). A less favorablearrangement of the P-O···H-C motif, e.g., in nucleotides of the canonical A-RNA, results in an effectivedumping of both spin-spin interactions and insignificant values of the NMR coupling constants. The presentwork indicates that quantum chemical calculations of the indirect spin-spin couplings across the P-O···H-C motif can help detect some rare but important backbone topologies, as seen for example in thereverse kink-turn. Measuring of 3J(P,C) and 2J(P,H) couplings can therefore provide critical constraints onthe NA base and phosphate geometry and help to determine the structure of NAs.
J > 1 Hz). A less favorablearrangement of the P-O···H-C motif, e.g., in nucleotides of the canonical A-RNA, results in an effectivedumping of both spin-spin interactions and insignificant values of the NMR coupling constants. The presentwork indicates that quantum chemical calculations of the indirect spin-spin couplings across the P-O···H-C motif can help detect some rare but important backbone topologies, as seen for example in thereverse kink-turn. Measuring of 3J(P,C) and 2J(P,H) couplings can therefore provide critical constraints onthe NA base and phosphate geometry and help to determine the structure of NAs.