Skip to main content
. Author manuscript; available in PMC: 2017 Sep 13.
Published in final edited form as: Methods Enzymol. 2014;549:189–219. doi: 10.1016/B978-0-12-801122-5.00009-X

Figure 7.

Figure 7

31P NMR-based determination of pKa. A) The downfield shift of the phosphorus peak with a phosphorothioate substitution. The inset is an expansion of the boxed region at the lowest (5.12) and highest (8.98) pH. B) Plot of chemical shift of the phosphorus peaks versus pH for oligonucleotides containing a protonated A+•C wobble pair (solid and hollow circles) and a control oligonucleotide where the A+ •C wobble pair is replaced with a Watson-Crick base pair. The pKa can be determined by fitting the plot to Eq. (4). Adapted with permission from Moody et al. 2004. Copyright (2004) American Chemical Society.