Crambin in Phospholipid Vesicles: Circular Dichroism Analysis of Crystal Structure Relevance
Abstract
Crambin, a hydrophobic plant seed protein that exhibits sequence homology to membrane-active plant toxins, was incorporated into phospholipid vesicles. Circular dichroism spectroscopy indicates that its structure in vesicles is nearly identical to its structure in 60% ethanol solution, the solvent from which the protein was crystallized. The secondary structure predicted from the circular dichroism data of the ethanol solution closely resembles that determined by x-ray diffraction of the crystals. This agreement suggests that the x-ray structure may form a useful basis for modeling the structure and behavior of lipophilic plant toxins. Finally, because the structure of crambin has been determined in an organic solvent medium, it provides a protein standard for examination of the effect of solvent dipole moment on the circular dichroism spectra of proteins, which may be important for interpretation of data for membrane proteins.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- March 1984
- DOI:
- 10.1073/pnas.81.5.1406
- Bibcode:
- 1984PNAS...81.1406W