If you haven't already used it, I would certainly try the approach of microseeding into screens since you already have crystals
http://scripts.iucr.org/cgi-bin/paper?S0907444907007652 -- patr...@douglas.co.uk <mailto:patr...@douglas.co.uk> Douglas Instruments Ltd. DouglasHouse, EastGarston, Hungerford, Berkshire, RG177HD, UK Directors: Peter Baldock, Patrick Shaw Stewart http://www.douglas.co.uk/ <http://www.douglas.co.uk/> Tel: 44 (0) 148-864-9090 US toll-free 1-877-225-2034 Regd. England 2177994, VAT Reg. GB 480 7371 36 From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of HanJie_HCT Tai Sent: 17 May 2009 13:27 To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] How to improve crystal which is twinning? Hi, I have a 22kDa protein that the floopy N & C terminus have been deleted. It was crystallized in 35%MPD/0.1m Tris (pH 8.5)/0.2M/(NH4)2SO4 in 2 - 3 days. Previously, a few small twining crystals were grown in this condition. I tried Hampton Research 96-additive screen . Additives such as glycerol, dioxane, etc didn't work well to improve/reduce twining issue. The 0.3% DMSO is the best additive I found that can grow a single crystal in the 1(pro)+0.8(buff)+0.2(add) drop. However, If looking careful under microscope it may be some other crystals growing inside that single crystal(hardly see under the microscope, but I can see it in other drops). I conducted the x-ray diffraction experiment for this 0.1x 0.1 mm crystal for which no cryoprotectant is required. The highest resolution is 2A but there are a lot of smear on the diffraction pattern. Thus, the index procedures failed due to the crystal quality. Do you have any brilliant ideas to improve the crystal growing condition in my case in order to get a truly single crystal? regards, Heng ________________________________ Windows Live(tm): Keep your life in sync. Check it out. <http://windowslive.com/explore?ocid=TXT_TAGLM_BR_life_in_synch_052009>
