Figure 5 - full size

 

Figure 5.
Figure 5. Comparison of the NMR solution structure and the X-ray crystal structure [Ke 1992] of free CypA. (a) Stereo view of the polypeptide backbones after superposition for minimal RMSD between the heavy atoms N, C^α and C′ of residues 2 to 165. A spline function was drawn through the C^α positions. In the NMR structure (gray) the radius of the cylindrical rod corresponds to the mean of the global displacements, D[glob]^bb (Figure 3(b), among the 20 energy-minimized NMR conformers, and in the crystal structure (orange) to the converted temperature factors, Image , of the C^α atoms. In addition, the position of CsA (yellow) in the NMR structure of the CypA-CsA complex [Spitzfaden et al 1994] is shown, as obtained after superposition of the backbone heavy atoms N, C^α and C′ of residues 2 to 165 of CypA in the complex and in the free form for minimal RMSD. (b) Stereo view of the crystal contacts in the loop containing His70. The backbone and selected side-chains of the mean NMR structure (gray) and the crystal structure (orange) are shown after superposition of the backbone heavy atoms N, C^α and C′ of residues 2 to 165 for minimal RMSD. A neighboring CypA molecule in the crystal lattice is shown in dark red. Intermolecular hydrogen bonds and salt bridges between the neighboring CypA molecules in the crystal lattice are indicated with yellow broken lines. Numbers indicate the sequence positions of selected residues. (c) Stereo view of a heavy-atom representation of residues 29 to 41 and Glu86 after local superposition of the backbone heavy atoms N, C^α and C′ for minimal RMSD. The 20 DIANA conformers representing the NMR solution structure are shown in gray, and the crystal structure in orange. The residues shown form the first α-helix (residues 30 to 41) and a long-range N-cap. Helical and N-capping hydrogen bonds are represented with yellow and green broken lines, respectively (see the text for further details). (d) Stereo view of a heavy-atom representation of β-strands 4, 5 and 6 comprising residues 61 to 64, 97 to 100 and 112 to 115, respectively, after local superposition of the backbone heavy atoms N, C^α and C′ for minimal RMSD. Coloring as in (c), with the hydrogen bonds between the strands represented with yellow broken lines.

The above figure is reprinted by permission from Elsevier: J Mol Biol (1997, 272, 64-81) copyright 1997.