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Hi Vish Thank you for pointing out the mistake in my previous message! I did mean a still image in a room temp. capillary mount. Still indeed means no rocking. Thierry From: Viswanathan Chandrasekaran [mailto:[log in to unmask]] Sent: Thursday, January 21, 2016 3:41 PM To: Fischmann, Thierry Subject: RE: [ccp4bb] Poor resolution of protein crystal Dear Thierry, From your email in the recent CCP4BB thread, “The 1st step is to take a still diffraction image to check whether the freezing damaged the crystals or the crystals grew poorly in the 1st place.” What is the rationale behind this test? By still image do you mean no rocking of the crystal during the exposure? I thought that a room temperature capillary mount was needed to test whether cryocooling caused the damage? Thanks, Vish From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Fischmann, Thierry Sent: 20 January 2016 13:23 To: [log in to unmask]<mailto:[log in to unmask]> Subject: Re: [ccp4bb] Poor resolution of protein crystal Your crystal is very mosaic etc. The 1st step is to take a still diffraction image to check whether the freezing damaged the crystals or the crystals grew poorly in the 1st place. There are many approaches to try and improve crystal quality, but they all share the same characteristics: - they work in a few cases and not in many others - What is going to work in a new case is typically unpredictable Considering your crystallization conditions, one suggestion (and I mean one of many) is to vary the cation (Mg2+ Ca2+ etc) concentration and look at some more (Mn2+ Zn2+ etc.) Other good tips can be found in the CCP4 wiki : http://strucbio.biologie.uni-konstanz.de/ccp4wiki/index.php/Main_Page I’ll add one : use one of the tennis racket shaped loop if your crystal grow as a thin plate, and either one of these or an elliptical loop if the crystal is needle-shaped. This has made a world of difference if a few (see above) cases I’ve worked on …. Good luck Thierry From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Prerana G. Sent: Wednesday, January 20, 2016 12:03 AM To: [log in to unmask]<mailto:[log in to unmask]> Subject: [ccp4bb] Poor resolution of protein crystal Dear all, I have a question on how to improve the resolution of protein crystals. I am working on a protein which crystallizes in the following conditions 1) 0.1M Magnesium nitrate hexahydrate & 10% PEG 3350 2) 0.2M Calcium chloride dihydrate & 6-14% PEG 3350 3) 0.2M Calcium acetate hydrate & 6-14% PEG 3350 The crystals diffracted to a very low resolution (~ 4 Angst, kindly see the attached image) at home source. To prevent ice formation, different cryoprotectants such as glycerol, 2-methyl-2,4-pentanediol, PEG 400, PEG 3350, Hexanediol, were used. Any suggestion to improve the x-ray diffraction resolution will greatly help me. Thanking you. Prerana Notice: This e-mail message, together with any attachments, contains information of Merck & Co., Inc. (2000 Galloping Hill Road, Kenilworth, New Jersey, USA 07033), and/or its affiliates Direct contact information for affiliates is available at http://www.merck.com/contact/contacts.html) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system. Notice: This e-mail message, together with any attachments, contains information of Merck & Co., Inc. (2000 Galloping Hill Road, Kenilworth, New Jersey, USA 07033), and/or its affiliates Direct contact information for affiliates is available at http://www.merck.com/contact/contacts.html) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system.