[3DEM] CTF-correction of a protein-DNA assembly

Hans Elmlund hans.elmlund at mbfys.lu.se
Thu Jun 8 07:20:46 PDT 2006


**** Messages to this list are automatically archived ***
**** Please limit quoting of previous postings to the bare minimum ****

Dear cryo-electron microscopists,

I am currently working with a DNA bound protein complex using cryo-EM of
single-particles. The images are dominated by the dark contrast of the
DNA. What is the mechanism of contrast formation? Is it amplitude
contrast due to the phosphate backbone or is it inverted phase contrast
due to charge effects? If it is amplitude contrast, then I guess the
CTF-correction will be problematic, since difference in amplitude
contrast leads to difference in defocus? Is this a problem, and if so,
do you know any way around it? Or am I doomed to develop low defocus
images in stain and low-pass filter them? I would be most grateful for
some clarifications on this issue.

Best regards

Hans Elmlund
--
For information on how to subscribe/unsubscribe/etc., send mail to
3dem-request at 3dem.ucsd.edu with the text "help" in the body of the
message.



More information about the 3dem mailing list