Re: [ccp4bb] Bicelle Crystallisation

2013-12-13 Thread El Arnaout, Toufic
Hi Rhys, I hope you are well. The JOVE article for bicelles is nice, plz check the video. There is a table in the text section showing some structures that originated from crystals grown at 4-7 % bicelle conc. using not only the DMPC/CHAPSO mixture... The other parameter that everyone tries is

[ccp4bb] Mr Ashley Bray

2013-10-26 Thread El Arnaout, Toufic
Dear CCP4 community, I am very stunned to hear about the death of Mr. Ashley Bray. He was a friend and colleague when I was in Dublin, where he was doing his PhD in membrane protein crystallography. He knew many techniques and was dedicated to his work, and to become a good scientist. Ashley

Re: [ccp4bb] membrane protein optimization

2013-10-23 Thread El Arnaout, Toufic
Hi Frank, The previous suggestions are great. In my case, I had soft crystals (bend from 180° to ~130-140°) in the loop using the LCP but they still diffracted. There are a lot of heroic stories on how some people solved a structure, you should just try as many ways as possible (do not only

Re: [ccp4bb] Concentrating purified membrane protein

2013-07-15 Thread El Arnaout, Toufic
Hi, That is true, Michael.. can't remember the reference, but in some study they found that even if you use a higher MWCO (for example 100 kDa) with DDM (micelle 65-70 kDa), there is still 70-80 % retained detergent in the protein sample. Raji, another thing I would like to say is that the

Re: [ccp4bb] off topic: good peak on gel filtration

2013-07-01 Thread El Arnaout, Toufic
Hello Peter, In addition to the great comments/details, please check the following points I have now in mind.. since you want to relate the size exclusion peak/profile to the crystallization: - occasionnaly, some perfect peaks that you might think are homogeneous actually correspond to a sample

Re: [ccp4bb] Off-topic: NMR and crystallography

2013-06-11 Thread El Arnaout, Toufic
Hi Theresa, Here is a comparison between both methods (Table under 6-Summary):http://www.cryst.bbk.ac.uk/pps97/assignments/projects/ambrus/html.htm If you would like to have an idea about structures of membrane proteins (why was NMR used and what answers they got etc) solved by NMR to