We show that salt bridges involving lysines can be detected by deuterium isotope effects on NMR chemical shifts of the sidechain amine. Lys27 in the ribonuclease barnase is salt bridged, and mutation of Arg69 to Lys retains a partially buried salt bridge. The salt bridges are functionally important.
Chemical Communications, 2013, Vol 49, p. 9824-9826
lysines; salt bridges; isotope effects; barnase; proteins