Electronmicroscopy of α-latrotoxin from the venom of black widow spider Latrodectus mactans tredecimguttatus
A. V. Lunev, V. V.Demin, O. I. Zaitsev, S. I. Spadar, E. V. Grishin
M. M. Shemyakin Institute of Bioorganic Chemistry, Academy of Sciences of the USSR, Moscow
Abstract: Two-dimensional crystals of α-latrotoxin from the venom of black widow spider (Latrodectus mactans tredeciinguttatus) were studied by the negative staining electron microscopy. Two-dimensional crystals were obtained by adsorption of the protein solution with a high Mg2+ concentration on carbon-coated electron microscopy grids. The crystals were about 0.4 mkm in size, had the unit cell parameters: a=b=15.55 nm, γ=90°, p4 plane group symmetry. The contour map of a stain-excluding region of such crystals was calculated by the Fourier-filtering procedure at about 4 nm resolution
The calculation of molecular weight of the unit cell, with the symmetry p4 taken into account, showed that α-latrotoxin particles, revealed by negative staining, consisted of 4 or 8 protomers.
Russian Journal of Bioorganic Chemistry 1991, 17 (8):1021-1026