Theoretical calculation of layer geometry in rotary shadowed models of membrane-associated particles.

The geometry of the evaporated metal layer on models of membrane-associated particles has been calculated theoretically and the respective density profiles have been estimated. The models were a hollow cylinder, a hemisphere and a rotary ellipsoid substituting the freeze-fracture appearance of gap junction connexons and globular integral membrane proteins respectively. These calculations may be used as a help for choosing an optimal compromise between shadowing angle and layer thickness. They furthermore provide a basis for assaying the extent of shadowing artefacts such as decoration and lead to a more accurate interpretation of rotary shadowed structures.