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Point‐projection imaging of macromolecular contours
Author(s) -
Panitz J. A.
Publication year - 1982
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1982.tb00319.x
Subject(s) - magnification , optics , materials science , resolution (logic) , projection (relational algebra) , microscope , cluster (spacecraft) , physics , algorithm , artificial intelligence , computer science , programming language
SUMMARY A point‐projection microscope is described which uses an electric field of several volts per nanometre to generate ions from a layer of benzene condensed in high vacuum on to the apex of a cryogenically cooled field‐emitter tip. Clusters of ferritin (a spherical protein molecule) embedded in the layer, have been imaged by exposing their contours during controlled field‐desorption. Image contrast is high. A magnification of 2 times 10 5 has been achieved at a spatial resolution estimated to be better than 3 nm. Three‐dimensional reconstructions of cluster morphology from a series of molecular contours are in qualitative agreement with transmission‐electron micrographs of the ferritin covered emitter apex. Reproducibility of the cluster contours, and TEM images of the apex before and after imaging suggest that the imaging procedure is nondestructive.