Mitch,
For discernment of Sodium versus Potassium, you could also look at the bonding
distances and coordination of the metal present. Ran into this problem back in
the day. Check out Figure 6 C,D in the following pub:
https://pubs.acs.org/doi/10.1021/bi060653d
Scott
--
Scott Pegan
Profess
You can also look at your anomalous maps. For most
energies/wavelengths used to
collect protein data, f" for K will be just under 2x the f" for S
while for Na f"
will be much less (0.2-0.25 of S). So you can use S atom anomalous as
an internal reference.
If you see anomalous peaks at your S a
