Crystallization of type I chloramphenicol acetyltransferase: an approach based on the concept of ionic strength reducers.
Chloramphenicol acetyltransferase (CAT) is responsible for bacterial resistance to chloramphenicol. It catalyzes inactivation of the antibiotic by acetyl-group transfer from acetyl CoA to one or both hydroxyl groups of chloramphenicol. Type I CAT possesses some unique properties which are not observed in other CAT variants. Type I CAT overexpressed in Escherichia coli was purified and crystals with a resolution limit of 2.22 A have been obtained using a novel procedure which is based on the concept of 'ionic strength reducers'. The crystals have the symmetry of space group P1 and unit-cell parameters a = 96.46, b = 113.86, c = 114.21 A, alpha = 119.9, beta = 94.1, gamma = 98.6 degrees. These dimensions are consistent with four to six trimers per unit cell, corresponding to a solvent fraction ranging from 65 to 47%.
Andreeva
A E
AE
University of Chemical Technology and Metallurgy, Department of Biotechnology, Sofia 1756, Bulgaria.
Borissova
B E
BE
Mironova
R
R
Glykos
N M
NM
Kotsifaki
D
D
Ivanov
I
I
Krysteva
M
M
Kokkinidis
M
M
D015500:Chloramphenicol O-Acetyltransferase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D014644:Genetic Variation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification
D011994:Recombinant Proteins; D015500:Chloramphenicol O-Acetyltransferase