Abstract:Human serum albumin(HSA),the most abundant protein in plasma,with functions of regulating blood protein,fatty acids,hormones,drugs,and representing the main determinant of plasma oncotic pressure,providing a depot and carrier for many endogenous and exogenous compounds. The engineering pichia pastorios GSll5/pPIC9K-rHSA was fermented by 50 L fermentor. Highly purified rHSA was separated from fermentation supernatant by ultra filter,Blue sepharose affinity chromatography,Phenyl sepharose hydrophobic chromatography and SP sepharose ion exchange chromatography purification．Eventually the purity of rHSA can reach more than 99.9%. Through screening crystallization conditions of rHSA,five conditions with precipitant of PEG 1500,PEG 3350,PEG 6000,MPEG 2000 and MPEG 5000 were obtained. The crystallization condition was hydrophobic and without strong reductant like DTT. Crystals of rHSA and pHSA with precipitant of MPEG 2000 were best for X ray diffraction,respectively the resolution were 3.4 ?魡 and 3.1 ?魡. Crystal structure of rHSA and pHSA were the same as a whole that obtained through molecular displacement method. The results provided reliable basis and foundation for the clinical application of rHSA and crystal structure study of HSA fusion proteins.
