Hi Rhys Following up on Santosh's post if you are visiting Diamond for your data collections we do have a Xenon cell available: http://www.diamond.ac.uk/mx-home/Equipment-on-Demand/Xe-Chamber.html
If you want to use it please let your local contact know in advance. Dave From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Santosh Panjikar Sent: 16 January 2014 01:55 To: ccp4bb Subject: Re: [ccp4bb] Best compounds for heavy atom soaks Dear Rhys, You may consider Xenon derivative, which could be prepared simply pressurizing the protein crystals in a xenon chamber. It does not require any modification of mother liquor. It just needs cryo-protectant where crystals are stable for at least one to two mins. Higher Pressure (20 to 40 bar) and 1-2 min incubation time are normally sufficient for binding of Xenon to proteins. Xenon binds to pre existing hydrophobic cavities of proteins by dispersion force. Xenon derivatives are highly isomorphous to native crystals. So SIRAS phasing could be efficient. However if you consider collecting data at longer wavelengths you could get anomalous signal from sulphur too. Weaker SAD or SIRAS phases from Xenon derivative could be used to bootstrap the Sulphur phasing. Similarly Kr pressurisation could be tried. MAD experiment can be performed at any tunable beamline but the disadvantage with this derivative is, it desorps quickly during cooling after pressurisation leaving out with lower than 50-60% occupancy. Success of the Xenon/Krypton derivatisation depends on size of the proteins and how stable your crystals are under cryo-protectant. The bigger the protein, higher the chance of Xe/Kr binding. best Santosh Santosh Panjikar, Ph.D. Scientist Australian Synchrotron 800 Blackburn Road Clayton VIC 3168 Australia Ph: +61-4-67770815 (mobile) +61-3-85404276 (office) ________________________________ -- This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail. Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message. Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom
