Direct determination of phospholipid lamellar structure at 0.34-nm resolution.
Low-dose, high-resolution electron microscopy combined with conventional direct-phasing methods based on the estimates of triplet-structure invariants are used to determine phase values for all observed electron-diffraction-structure factor magnitudes from epitaxially oriented multilamellar paracrystals of the phosphospholipid 1,2-dihexadecyl-sn-glycerophosphoethanolamine. The reverse Fourier transform of these phase-structure factors is a one-dimensional electrostatic potential map that strongly resembles the electron-density maps calculated from similar x-ray-diffraction data. Determination of the phase values for the electron-diffraction data with structure invariants alone is nearly as successful as the combined use of two separate methods, assigning values to 13 of the 16 reflections--i.e., the electrostatic potential map closely resembles the one calculated with all data.
Dorset
D L
DL
Electron Diffraction Department, Medical Foundation of Buffalo, Inc., NY 14203.
Beckmann
E
E
Zemlin
F
F
D003460:Crystallization; D008854:Microscopy, Electron; D008962:Models, Theoretical; D008968:Molecular Conformation; D010743:Phospholipids / Q000737:chemistry*; D014961:X-Ray Diffraction
D010743:Phospholipids