Shouldn’t it be possible to look at the ratio of peak heights of O’s versus S or P to figure out which is more likely? The must be thousands of examples in the pdb with which to determine the ratio, even if one restricts the analysis to “high resolution” structures.
JPK +++++++++++++++++++++++++++++++++++++++++++++++++ Jacob Pearson Keller Research Scientist / Looger Lab HHMI Janelia Research Campus 19700 Helix Dr, Ashburn, VA 20147 Desk: (571)209-4000 x3159 Cell: (301)592-7004 +++++++++++++++++++++++++++++++++++++++++++++++++ The content of this email is confidential and intended for the recipient specified in message only. It is strictly forbidden to share any part of this message with any third party, without a written consent of the sender. If you received this message by mistake, please reply to this message and follow with its deletion, so that we can ensure such a mistake does not occur in the future. From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> On Behalf Of Yu Qiu Sent: Sunday, February 17, 2019 9:11 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] SO4 or PO4 Hi Shijun, I had a similar issue a while ago that a acetylated lysine binding site was occupied by acetate from buffer. In this case, I would suggest trying crystallize in a conditions without SO4, e.g. using NH4Cl instead, if it is reproducible. Best, Yu From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of ??? Sent: Sunday, February 17, 2019 8:57 AM To: CCP4BB@JISCMAIL.AC.UK<mailto:CCP4BB@JISCMAIL.AC.UK> Subject: [EXTERNAL] Re: [ccp4bb] SO4 or PO4 Dear all Thanks for all your suggestions. PO4 is from my Ligand PI3P, but I cannot see the electron density of the PI3P tail, and the binding site is exactly there. While my crystal buffer salt is 50mM (NH4)2SO4, so I am afraid the SO4 occupied the PO4 position.BTW, I can see the other SO4 electron density in the other places, but is small than this one, and the diffraction resolution is 1.6A. Best Regards Shijun -----Original Messages----- From:"Roger Rowlett" <rrowl...@colgate.edu<mailto:rrowl...@colgate.edu>> Sent Time:2019-02-17 00:47:55 (Sunday) To: CCP4BB@JISCMAIL.AC.UK<mailto:CCP4BB@JISCMAIL.AC.UK> Cc: Subject: 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 donor to acceptor hydrogen bonding contacts. Sulfate rarely has donor to acceptor hydrogen bonding contacts, as it is SO4= at any reasonable pH. Roger Rowlett On Sat, Feb 16, 2019, 4:06 AM 张士军 <21620150150...@stu.xmu.edu.cn<mailto: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, 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 ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.jiscmail.ac.uk_cgi-2Dbin_webadmin-3FSUBED1-3DCCP4BB-26A-3D1&d=DwMGaQ&c=Dbf9zoswcQ-CRvvI7VX5j3HvibIuT3ZiarcKl5qtMPo&r=J-_EnZntmgYSuwGfqAanOKOx4S6mpcVpSKdhaTM92OY&m=Kl40SjTwjL17lOBJyHjftyBGU5mhSWNptFzJ-gQMsQ4&s=Sk-9VtK7KIJXB1dvm2TarZMv6hpUype4vHKSOfMTqyA&e=> ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.jiscmail.ac.uk_cgi-2Dbin_webadmin-3FSUBED1-3DCCP4BB-26A-3D1&d=DwMGaQ&c=Dbf9zoswcQ-CRvvI7VX5j3HvibIuT3ZiarcKl5qtMPo&r=J-_EnZntmgYSuwGfqAanOKOx4S6mpcVpSKdhaTM92OY&m=Kl40SjTwjL17lOBJyHjftyBGU5mhSWNptFzJ-gQMsQ4&s=Sk-9VtK7KIJXB1dvm2TarZMv6hpUype4vHKSOfMTqyA&e=> ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.jiscmail.ac.uk_cgi-2Dbin_webadmin-3FSUBED1-3DCCP4BB-26A-3D1&d=DwMGaQ&c=Dbf9zoswcQ-CRvvI7VX5j3HvibIuT3ZiarcKl5qtMPo&r=J-_EnZntmgYSuwGfqAanOKOx4S6mpcVpSKdhaTM92OY&m=Kl40SjTwjL17lOBJyHjftyBGU5mhSWNptFzJ-gQMsQ4&s=Sk-9VtK7KIJXB1dvm2TarZMv6hpUype4vHKSOfMTqyA&e=> ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
