Fig 2.
(A) Electron density for CsA, from a 2Fo − Fc map calculated before CsA was added to the model. Contour is at 1 σ. The final CsA model is shown in the density. (B) CsA conformation before and after binding to Cn. Superposition of Cyp-Cn-bound CsA (dark color) onto Cyp-bound CsA (lighter color, PDB code ) based on the least-squares fit of the two Cyp molecules. (Note that there are 10 virtually identical CsA/Cyp complexes in one asymmetric unit in this crystal form, we chose the first one for structural comparison.) The following abbreviations are used for the modified amino acids of CsA. Bmt, 4-[(E)-2-butenyl]-4,N-dimethyl threonine; Aba, α-amino butyric acid; Sar, sarcosine; Ala, l-alanine; Dal, d-alanine; Mle, N-methyl leucine; Mva, N-methyl valine.