NMR methods for determining disulfide-bond connectivities

Animal toxins are the major class of secreted disulfide-rich proteins, with ∼70% containing two or more disulfide bonds. Incorrect pairing of these disulfide bonds typically leads to a non-native three-dimensional fold accompanied by a loss of protein function. Determination of the native disulfide-bond framework is therefore a key component in the structural characterization of toxins. In this article, we review NMR approaches for elucidation of disulfide-bond connectivities. A major advantage of these NMR approaches is that they are non-invasive, leaving the sample intact at the end of the analysis for use in other studies.