Pischia expression

[PWHoward]

Pischia has produced a full length transcription factor for me that E.
coli just couldn't hack.  It was poly His tagged and was purified easily
in one step.  When using Ni++ chelate resin I have found that binding your
protein to the resin in 0.6 M ammonium sulfate substantially increases
yield.  The high salt can be washed of the resin just prior to elution
with 0.25 M imidazole.