A comparison of X‐ray and NMR structures for human endothelin‐1

Direct comparisons between the recently solved X‐ray and NMR structures of human endothelin‐1 with respect to secondary structure, RMS deviations, surface accessibilities, and side‐chain conformers indicate important differences in conformation, especially in the C‐terminus, but also in the central loop region, that are important for defining the specificity of binding. These differences are larger than seen for other X‐ray and NMR structures that have been compared. Comparisons between the X‐ray structure and the NMR NOE constraints highlight the regions of flexibility and environment‐induced diversity in the endothelin structures.