Apoptotic regulation has been implicated in many human diseases, including cancer,
autoimmune disease, inflammation and neuro degradation. Mapping up critical apoptosis
regulators is a strategy for the development of new therapies [1, 2].Present work
highlights optimization of heterologous expression conditions for the X-linked inhibitor
of apoptosis protein (XIAP). Genes of target protein containing pGEX-4T vector was
transformed in chemically competent E. coli Rosetta (TM)(DE3)pLysS cells. The recombinant
construct contained a glutathione S-transferase (GST) fusion partner, which assured
the purification of the protein by affinity chromatography. In the next step we examined
the growth dynamics of the expression culture in M9 minimal medium, meanwhile we also
determined the appropriate time of induction. Following this we carried out the optimization
of expression, examining the expression's effectiveness under different conditions.
On the basis of these fermentation experiments the target protein expression was the
most prominent at 18 degrees C with 0.2 mM IPTG induction for 12 hours. During large
scale fermentation experiments, we followed the optical density (OD), dry cell weight
and substrate utilization. Finally, recombinant protein expression inhancement in
the presence of 3% ethanol was successfully achieved in bioreactor. In this case the
target protein was expressed in inclusion bodies, therefore solubilisation and refolding
is necessary.
