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Effects of fixing and staining on images of tropomyosin Mg‐paracrystals
Author(s) -
Lamvik Michael K.,
White Linda R.,
EikNes Kristen B.
Publication year - 1984
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.1365-2818.1984.tb02502.x
Subject(s) - tropomyosin , staining , negative stain , chemistry , crystallography , biophysics , microbiology and biotechnology , actin , biochemistry , biology , pathology , optics , medicine , physics , electron microscope
SUMMARY Tropomyosin Mg‐paracrystals have been studied by positive and negative staining with uranyl acetate and sodium phosphotungstate, either unfixed or fixed with glutaraldehyde. Fixation causes changes in some of the paracrystal bands. Some of the bands are more intense when a positively‐charged staining ion is used than when a negatively‐charged ion is used, in both negative and positive‐staining techniques. This result rules out the suggestion that negative staining is not affected by the charge of the stain in tropomyosin, and agrees with findings in other specimens. Therefore it is unlikely that any simple parameter based on residue size can be used to predict the image intensity from the amino acid sequence for tropomyosin. These staining patterns cast doubt on the earlier interpretation of a prominent white band in the paracrystal as an overlap of alpha‐helical molecular ends.