structural probes in quadruplex nucleic acid structure determination by nmr结构在四倍的核酸探针结构由nmr测定.pdf

Molecules 2012, 17, 13073-13086; doi:10.3390/molecules171113073 OPEN ACCESS molecules ISSN 1420-3049 /journal/molecules Review Structural Probes in Quadruplex Nucleic Acid Structure Determination by NMR Andreas Ioannis Karsisiotis and Mateus Webba da Silva * Biomedical Sciences Research Institute, University of Ulster, Cromore Road, Coleraine, Co. Londonderry BT52 1SA, UK * Author to whom correspondence should be addressed; E-Mail: mm.webba-da-silva@ulster.ac.uk; Tel.: +44-28-7032-4009. Received: 24 September 2012; in revised form: 1 November 2012 / Accepted: 1 November 2012 / Published: 5 November 2012 Abstract: Traditionally, isotope-labelled DNA and RNA have been fundamental to nucleic acid structural studies by NMR. Four-stranded nucleic acid architectures studies increasingly benefit from a plethora of nucleotide conjugates for resonance assignments, the identification of hydrogen bond alignments, and improving the population of preferred species within equilibria. In this paper, we review their use for these purposes. Most importantly we identify reasons for the failure of some modifications to result in quadruplex formation. Keywords: chemical modifications; 8-bromoguanosine; quadruplex; 2,6-diaminopurine; LNA; inosine; 8-O-methylguanine; 8-methylguanine; 5-bromouracil; riboguanosine 1. Introduction DNA usually adopts a structure in which its strands are connected through hydrogen bond alignments of G:C and A:T into a to