Pancreatic spasmolytic polypeptide: Crystallization, circular dichroism analysis, and preliminary X-ray diffraction studies
Article first published online: 3 FEB 2004
Copyright © 1992 Wiley-Liss, Inc.
Proteins: Structure, Function, and Bioinformatics
Volume 13, Issue 4, pages 364–368, August 1992
How to Cite
Gajhede, M., Thim, L., Jørgensen, K. H. and Melberg, S. G. (1992), Pancreatic spasmolytic polypeptide: Crystallization, circular dichroism analysis, and preliminary X-ray diffraction studies. Proteins, 13: 364–368. doi: 10.1002/prot.340130408
- Issue published online: 3 FEB 2004
- Article first published online: 3 FEB 2004
- Manuscript Accepted: 12 NOV 1991
- Manuscript Received: 15 OCT 1991
- pancreatic spasmolytic polypeptide;
- porcine pancreas;
- hanging drop vapor diffusion method;
- circular dichroism analysis;
- porcine insulin
Pancreatic spasmolytic polypeptide (PSP) isolated from porcine pancreas has been crystallized by the hanging drop vapor diffusion method. Crystals suitable for X-ray diffraction analysis were grown at pH 4.7 from a solution of 6% saturated ammonium sulfate. The space group is orthorhombic I222 or I212121 with unit cell parameters a = 54.38 Å, b = 72.29 Å, and c = 180.85 Å. There are three molecules of PSP per asymmetric unit and a water content of 46.9%. The crystals diffracts to an estimated resolution of 2.7 Å.
The far-UV CD spectrum of PSP shows some exceptional features which cannot be accounted for thoroughly in terms of standard secondary structures commonly seen in protein CD spectroscopy. With this limitation, the secondary structure analysis predicts 15% α-helix, between 10 and 20% antiparallel β-strand, 10% parallel β-strand, 15% turn, and 25 to 40% of other structures. © 1992 Wiley-Liss, Inc.