Crystallization and preliminary X-ray analysis of thiaminase I from Bacillus thiaminolyticus: space group change upon freezing of crystals.
Thiaminase I (Mr = 42 100) from B. thiaminolyticus, expressed in E. coli, has been crystallized by the vapor-diffusion method. Three crystal forms, two of which grew from 0.1 M sodium acetate (pH = 4.6), 0.2 M ammonium sulfate and 30%(w/v) PEG 2000, have been examined by X-ray analysis. One crystal form diffracted to 2.5 A at room temperature, was orthorhombic, and had unit-cell edges of a = 87.7, b = 120.5 and c = 76.7 A with space group P212121. A self-Patterson map showed a strong peak indicating noncrystallographic translational pseudosymmetry with (u, v, w) = (0.03, 0.0, 0.5). When these crystals were frozen at liquid-nitrogen temperatures, a second crystal form was observed which had unit-cell dimensions a = 85.5, b = 117.5 and c = 36.6 A with space group P21212. A third crystal form grew from 0.1 M Tris (pH = 8.5), 0.2 M sodium acetate trihydrate and 28%(w/v) PEG 6000 to produce orthorhombic crystals of space group P212121 with cell edges of a = 114.4, b = 123.1 and c = 92.5 A.
Section of Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, NY 14853, USA.
N
N
Campobasso
J
J
Begun
C A
CA
Costello
T P
TP
Begley
S E
SE
Ealick
D019883:Alkyl and Aryl Transferases / Q000737:chemistry*; D001407:Bacillus / Q000201:enzymology*; D003460:Crystallization; D018360:Crystallography, X-Ray; D005615:Freezing; D011994:Recombinant Proteins / Q000737:chemistry
D011994:Recombinant Proteins; D019883:Alkyl and Aryl Transferases; C022737:thiamin pyridinylase