Crystallization of yeast iso-2-cytochrome c using a novel hair seeding technique.
A hair seeding technique has been developed to obtain diffraction quality crystals of yeast (Saccharomyces cerevisiae) iso-2-cytochrome c, a model for studies of protein folding and biological electron transfer reactions. Deep red crystals of this protein were obtained from 88 to 92% saturated solutions of ammonium sulfate containing 20 mg protein/ml, 0.1 M-sodium phoshate, 0.3 M-sodium chloride, 0.04 M-dithiothreitol and adjusted to phosphate, 0.3 M-sodium chloride, 0.04 M-dithiothreitol and adjusted to pH 6.0. Rapid crystal growth was observed, but only along the path of the seeding hair stroke. The space group is P4(3)2(1)2 (or P4(1)2(1)2) with a = b = 36.4 A, c = 137.8 A (1 A = 0.1 nm) and Z = 8. Crystals are stable in the X-ray beam for more than 10 days and diffract to at least 2.5 A resolution. The same hair seeding methodology has proven useful in obtaining crystals of specifically designed mutant iso-2 proteins and in other protein systems where consistent crystal growth had previously proven difficult to attain.
Leung
C J
CJ
Department of Biochemistry, University of British Columbia Vancouver, Canada.
Nall
B T
BT
Brayer
G D
GD
D003460:Crystallization; D003574:Cytochrome c Group; D045304:Cytochromes c; D008722:Methods; D012441:Saccharomyces cerevisiae; D014961:X-Ray Diffraction
D003574:Cytochrome c Group; C032139:iso-2-cytochrome C; D045304:Cytochromes c