Dear CCP4ers, Apologies for a non-CCP4 question. I have been trying to streak seed one of my protein crystals(clusters of needles) grown in the presence of Ammonium sulphate. I set up the drops for equilibration overnight. When I opened the coverslips to begin streak seeding (the next day), within a few seconds the drops began to show precipitation. I must also mention that the protein concentration in the drops was lowered to 2/3rd of that in the original condition. Additionally, the conc. of ammonium sulfate was dropped to about 75% of that present in the original condition. Should I (a) lower the protein conc. further, (b) lower the precipitant conc. more, (c) keep for a longer equilibration period, (d) try a,b.c in tandem, (e) try sitting drops?
Many thanks in advance, Amit
