Dear all,
I am trying to reproduce some protein crystals. The protein I am getting
after cutting the his tag is very pure. I am using the reported protein
concentration. The cofactor and EDTA needs to be added externally. The
condition has calcium acetate, peg 4k and sodium acetate buffer.
Hi,
you changed something, and although it seems very small a change, this
can make a difference between crystals and non-crystals. And removing
the His-Tag is not a small change, since it influences the net charge.
The first thing to try is micro and macro-seeding. If they don't work,
you may
troublesome.
BR
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of dusky dew
Sent: Montag, 14. Juli 2014 13:44
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] cannot reproduce crystals
Dear all,
I am trying to reproduce some protein crystals. The protein I am getting after
cutting
You may unleash a deluge of anecdotes and horror stories, but this is quite
common. I have experienced this many times, and you just need to step back and
ask yourself what is being done differently:
1. Are all materials used in the preparation of the protein the same
(suppliers, sources,
'oil separation and light ppt' is not necesserily an indicator that
something is wrong with your crystallization condition. Actually,
there are quite a few proteins that only crystallize in conditions
with oil/water-like phase separation. Some crystals even appear WITHIN
the oily drops
