Regularly alternating L,D-peptides. I. The double-stranded left-handed antiparallel β-helix in the structure of Boc-(L-Val-D-Val)4-OMe
Article first published online: 1 FEB 2004
Copyright © 1989 John Wiley & Sons, Inc.
Volume 28, Issue 1, pages 193–201, January 1989
How to Cite
Di Blasio, B., Benedetti, E., Pavone, V., Pedone, C., Spiniello, O. and Lorenzi, G. P. (1989), Regularly alternating L,D-peptides. I. The double-stranded left-handed antiparallel β-helix in the structure of Boc-(L-Val-D-Val)4-OMe. Biopolymers, 28: 193–201. doi: 10.1002/bip.360280121
- Issue published online: 1 FEB 2004
- Article first published online: 1 FEB 2004
- Manuscript Accepted: 1 AUG 1988
- Manuscript Received: 5 JUL 1988
The structure of Boc-(L-Val-D-Val)4-OMe has been determined by x-ray single-crystal diffraction analysis. The octapeptide crystallizes in the trigonal system, space group P3221 with a = b = 12.760 Å, c = 63.190 Å and Z = 6. The independent unit is represented by one octapeptide chain. The structure has been solved by direct methods and it was anisotropically refined by least-squares procedures to a final R value of 0.08 for the 3018 “observed” reflections. One molecule of water was also located in the unit cell. Two octapeptide chains, related by a crystallographic binary axis, wind up around each other giving rise to a double-stranded left-handed antiparallel β5.6-helix. The dimer, stabilized by 14 interstrand NH ⃛OC hydrogen bonds, can be regarded as a cylinder with an hydrophilic inner core represented by the peptide units and an hydrophobic exterior of isopropyl groups. The inner diameter of the cylinder is 5.1 Å.