NS versus cryo

[Denis Chretien]

One small comment concerning negative-stain versus cryo-EM of 
frozen-hydrated specimens. One of the best advantages of cryo-EM is 
that it preserves the aqueous environment of the specimen, not only 
water, but also pH or ionic-strength. This is not the case with 
negative stain and the overall conformation of the macromolecular 
assemblies can be drastically modified by these environmental 
changes. If the only goal of three-dimensional reconstruction is to 
get "a" structure, then negative-staining is probably fine. However, 
if you want to interpret your structure in terms of its function, 
then cryo-EM is - to my opinion- the only way to go.

_____________________________________
Denis Chretien
Equipe "Structure et Dynamique du Cytosquelette"
UMR 6026 "Interactions Cellulaires et Moleculaires"
Universite de Rennes 1
Campus de Beaulieu, Bt 13
35042 RENNES Cedex
FRANCE
_____________________________________
tel: +33 (0) 2 23 23 67 64
      +33 (0) 6 62 00 84 57
fax: +33 (0) 2 23 23 50 48
email: denis.chretien at univ-rennes1.fr
http://www.sdc.univ-rennes1.fr/
_____________________________________

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