ISSN:
0741-0581
Keywords:
Two-dimensional crystals
;
Cholera toxin
;
Electron crystallographic analysis
;
Oligomeric structure
;
Negative staining
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Natural Sciences in General
Notes:
Two-dimensional arraysThe term array is used to describe a regular arrangement of motifs without implying the existence of translational symmetry elements between motifs, by distinction with a crystal. of cholera toxin B-subunit (CTB) have been obtained by specific interaction with lipid films, as described by Ludwig et al. (1986). The relationship between two types of array, of either rectangular or hexagonal geometry, was analyzed using crystallographic methods of electron image analysis. Our results showed that the type of array obtained was highly dependent on the negative stain used and that both arrays presented related lattice parameters, indicating that they originated from a common unstained structure. Image analysis of hexagonal arrays at 17 Å resolution revealed variable CTB projected structures, ranging from annularly symmetric particles to highly asymmetric particles, very distinct from the pentameric structure resolved from rectangular crystals. The present data suggest that hexagonal arrays result from an imperfect staining of CTB rectangular crystals. The staining distortion is such that the stain layer does not match faithfully the pentameric protein distribution whereas the regular organization of the specimen is maintained.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jemt.1060180407
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