[ccp4bb] Protein Purification Problem

2014-01-30 Thread Anindito Sen
Dear All, This may be slightly off-the-track question but your feedback will be very much appreciated. The situation is- I obtain a very low amount of the protein of my interest (a hetro-dimer) from the construct I am using (only 8% of the total amount of protein obtained is the protein of my

Re: [ccp4bb] Protein Purification Problem

2014-01-30 Thread FOOS Nicolas
with Circular dichroisme or DLS). Hope to help you. Nicolas De : CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] de la part de Anindito Sen [andysen.to...@gmail.com] Envoyé : jeudi 30 janvier 2014 14:17 À : CCP4BB@JISCMAIL.AC.UK Objet : [ccp4bb] Protein

Re: [ccp4bb] Protein Purification Problem

2014-01-30 Thread Roger Rowlett
Do you really need to remove the NaCl? Some ionic strength is often necessary to stabilize proteins. Our routine purification buffers all contain at least 100 mM NaCl. This will not usually interfere with crystallization screening. To minimize the probability of aggregation, you need to (1)

Re: [ccp4bb] Protein Purification Problem

2014-01-30 Thread Anindito Sen
Dear All, 1st of all , Thanks for the very quick feedback. I will answer your questions to make the picture more clear- Nicolas- Yes the dimer is co-expressed. Almost all the protein is in the sup and not in the pellet. Multiple-step dialysis has failed. I have been trying various controls