[ccp4bb] SO4 or PO4

Dear all I have got a crystal grown at the condition both have ion of SO4 and PO4, and the diffraction resolution is very well, but the problem is coming: how to tell which is which just from electron density? I think they are exactly same. Thanks a lot !!! Beat Regards Shijun ##

Re: [ccp4bb] SO4 or PO4

How about collect data at sulfur peak. You might see anomalous peak for sulfur. Jinyu On Sat, Feb 16, 2019 at 4:07 AM 张士军 <21620150150...@stu.xmu.edu.cn> wrote: > Dear all > > I have got a crystal grown at the condition both have ion of SO4 and PO4, > and the diffraction resolution is very well,

Re: [ccp4bb] SO4 or PO4

Two things to look at that could provide a clue: Examine the anomalous map for some density over the central atom. Sulfur will often, but not always have significant anomalous density depending on the wavelength and quality of data set. Phosphate is normally HPO4= or H2PO4-. Look for phosphate do

[ccp4bb] Warning - ccp4 update 7.0.069 breaks ccp4i2 on MacBook running Mojave (v 10.14.2)

Hi All, I installed the latest ccp4 update on my MacBook through the CCP4i2 update manager. After doing so, refmac appeared to be broken. I tried to restart the I2 GUI but it refused to even after a reboot. Eventually I got running again by uninstalling this update through the CCP4i update mana

[ccp4bb] Fwd: [ccp4bb] SO4 or PO4

S has about 0.56 anomalous electrons at 8 keV, whereas P has about 0.44. This is a small difference between two weak signals—unlikely to give a clear result. If you could get to the sulfur & phosphorus edges, then you could (in principle) answer this, but that’s a very hard experiment to accompl

Re: [ccp4bb] SO4 or PO4

Anomalous is the way to go but it helps to think about the final concentrations used. With 50 mM PO4 (buffer) and 2 M  SO4 (ammonium sulfate) most "bindin sites in quesiton" will be occupied by SO4... My 2 cents Jeroen On Sat, Feb 16, 2019 at 4:07 AM 张士军 <21620150150...@stu.xmu.edu.cn

Re: [ccp4bb] Fwd: [ccp4bb] SO4 or PO4

This can be done at Diamond I23 beamline. https://doi.org/10.1016/j.nimb.2016.12.005 Best regards, Jan Dne 16.02.2019 v 18:49 Patrick Loll napsal(a): > S has about 0.56 anomalous electrons at 8 keV, whereas P has about > 0.44. This is a small difference between two weak signals—unlikely to > gi