Hello all,

I am currently trying to crystallize a protein which produced thin needles, after standardizing the expansion plates, i improved the dimensions of the needles but, now i am planning to do some soaking experiments and i am unable to reproduce the expansion conditions and the most recent expansion trial, there was heavy precipitation in the drop.

My hit conditions are usually around : HEPES(100mM), PEG 3350(24-28%) and NaCl(200-275mM) @ 17C.

My protein stocks were initially purified with HEPES and salt(final buffer after GF) but, the last batch was purified for some other purposes without any salt(only HEPES in final buffer), this could a possible explanation as to why my most recent attempts of crystallization led to precipitation in the drop.

But, i am looking for advice for any other explanations to be aware of for future trials.