Electron microscopy of proteins

[David Green]

Dr. Christian Kupfer wrote:

> I have some EM-Pictures of protein-komplexes bound to DNA.
> I can determine the size of the proteins in angstroms, because
> I know the size of the DNA.
>
> Is there anybody who can tell me how to determine the molecular
> mass just by knowing the radius in angstroms? Or is there any good
> review/ book out there where I can find answers?
>
> thanks in advance
>
>         christian

 You could get a rough estimate by assuming close packing in the protein
to calculate the expected number of heavy atoms and then plug in an
average heavy atom mass (14 is probably a good number).  Note that this
will only give you only an estimate of the mass (maybe to an order of
magnitude?).

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David F. Green
Department of Chemistry
Massachusetts Institute of Technology
77 Massachusetts Ave., Rm. 6-133
Cambridge, MA 02139

E-mail: dfgreen at lms.mit.edu
Phone: (617) 258-6229
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