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[ccp4bb]: Co-crystallisation with hydrophobic ligands

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Many thanks to everyone who emailed, suggestions were really helpful.
Here is a summary of responses:

David Schuller:

1.  Co-concentrate ligand with protein:   (This is actually something I
tried before posting my question;  it seems to work with some ligands
but with others concentration causes both protein and ligand to

Gitay Kryger & Jeroen Brandsen:

2.  Soak/Co-crystallise the crystal in drop containing solid ligand.

George Kontopidis:

3.  If Kd is slow, then excess of ligand is not required and unbound
ligand will be at low effective concentration anyway.  (In fact adding
excess will not give much greater occupancy).

Eiichi Tsuji:

4.  Use 1.3 dimethyl -2-imidazolidinone (DMI) instead of DMSO/DMF etc.
DMI is miscible in water and can tolerate up to 15%(v/v) against
protein.  (I hadnt heard of this solvent before, but im going to try

Michal Harel:

5.  Stir the ligand extensively in buffer or buffer+DMSO, then spin down

and use the solution in co-xtallization.