Has anyone ever done the experiment of switching precipitants/cryoprotectants and verifying that this crown-of-PEG around lysine goes away when you do?
Just curious, -James Holton MAD Scientist On 4/1/2019 4:26 PM, Paul Emsley wrote: Agreed. "PG4" - so that you don't have to go searching for it. On 02/04/19 00:22, Peat, Tom (Manufacturing, Parkville) wrote: Hello Zhen, PEG comes as a mixture and the weight given on the bottle is just the average molecular weight, so you don’t need any ‘cleavage’ to have smaller molecular weight PEGs present in your crystallisation cocktail. Try putting a small PEG in, it looks like it might fit. Cheers, tom From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of Zhen Luo Sent: Tuesday, 2 April 2019 9:59 AM To: [email protected]<mailto:[email protected]> Subject: [ccp4bb] unidentified crescent-shaped electron density Dear all, Could you please shed some light on what this crescent-shaped density around the lysine side chain might belong to? I now have two unrelated protein structures where this kind of density can be found surrounding a lysine side chain. One protein was crystallised in 0.1 M CaCl2 and 20% PEG 3350; the other in 10% PEG 20000, 20% PEG MME 550, 0.03 M CaCl2/MgCl2, 0.1 M MES/imidazole. Protein buffers contained 0.025 M HEPES and 0.15 M NaCl. None of these fitted in well. Could it be cleaved PEG? Any suggestion would be greatly appreciated. Thanks in advance! Best regards, Zhen Luo School of Chemistry and Molecular Biosciences The University of Queensland, Australia ________________________________ 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
