Crystallization of tuna ferricytochrome c at low ionic strength.
Previous crystallographic studies of tuna ferricytochrome c have employed crystals grown from solutions of ammonium sulfate, corresponding to an ionic strength of 9.5 M (Takano, T., and Dickerson, R. E. (1981) J. Mol. Biol. 153, 95-115). To obtain a structure at a lower ionic strength, the ferric tuna protein was crystallized at neutral pH with polyethylene glycol at an ionic strength of 45 mM, These crystals (space group P2(1), a = 37.11 A, b = 107.66 A, c = 55.75 A, beta = 105.3 degrees) contain four molecules/asymmetric unit and grow to dimensions of 0.2 X 0.4 X 1.0 mm in 2-4 weeks. They diffract to beyond 1.8 A and are stable in the x-ray beam. We have recorded 28,198 unique Bragg reflections (83% of those possible) to a resolution of 1.89 A from a native crystal. We are undertaking a solution of this structure by the molecular replacement method.
Walter
M H
MH
Department of Biochemistry, Northwestern University, Evanston, Illinois 60208.
Westbrook
E M
EM
Tykodi
S
S
Uhm
A M
AM
Margoliash
E
E
D000818:Animals; D003460:Crystallization; D003574:Cytochrome c Group; D005399:Fishes / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D011092:Polyethylene Glycols; D014413:Tuna / Q000378:metabolism*; D014961:X-Ray Diffraction
D003574:Cytochrome c Group; D011092:Polyethylene Glycols