Crystallization of synthetic Escherichia coli-type lipid A.
Synthetic Escherichia coli-type lipid A formed hexagonal plate crystals when it was precipitated by the addition of 2 volumes of 95% ethanol containing 375 mM MgCl2 and incubated in 70% ethanol containing 250 mM MgCl2 at 4 C for 10 days. Analyses of crystals by electron diffraction and synchrotron X-ray diffraction showed that crystals consist of hexagonal lattices with the lattice constant (a side of the lozenge as a unit cell on the basal plane) of 4.62 angstrom and the longitudinal axis (perpendicular to the basal plane) of 49.3 +/- 1.3 angstrom. Results suggest that the previous finding that various kinds of R-form lipopolysaccharides crystallized but free lipid A isolated by acid hydrolysis from Re lipopolysaccharide did not crystallize under the same experimental conditions (Kato et al, J. Bacteriol., 172:1516-1528, 1990) is due to structural changes of lipid A occurring during the procedure of isolation of free lipid A.
Kato
N
N
Department of Bacteriology, Nagoya University School of Medicine, Japan.
Naito
S
S
Arakawa
Y
Y
Sugiyama
T
T
Ito
H
H
Ohta
M
M
Sasaki
K
K
D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry*; D008050:Lipid A / Q000737:chemistry*; D008854:Microscopy, Electron
D008050:Lipid A