Cholera Toxin Crystals Suitable for X-ray Diffraction
PAUL B. SIGLER 1,
MARY ELLEN DRUYAN 2,
HELEN CHILTON KIEFER 3, and
RICHARD A. FINKELSTEIN 4
1 Department of Biophysics and Theoretical Biology, University of Chicago, Chicago, Illinois 60637
2 Department of Biochemistry, Loyola University School of Dentistry, Maywood, Illinois 60153
3 Department of Biochemistry, Northwestern University Medical and Dental Schools, Chicago 60611
4 Department of Microbiology, University of Texas Southwestern Medical School, Dallas 75235
Large crystals of the cholera toxin were grown; their dimensions, symmetry (P21), order, and resistance to radiation make them ideally suited for a high-resolution x-ray structure determination. There is one molecule (approximately 84,000 daltons) per asymmetric unit, and therefore the lattice reveals no molecular symmetry. Two distinct bioassays indicate that the protein from dissolved crystals retains full biological activity.
Submitted on December 12, 1976
Revised on May 6, 1977
