Three-step purification of a fragment of the large immunophilin FKBP52

PPIases catalyze the interconversion of cis and trans isomers of peptidyl-p rolyl (Xaa-Pro) bonds in peptide and protein substrates. The PPIase family comprises three subfamilies, two of which interact with immunosuppressant d rugs and are therefore termed immunophilins. One subgroup of the immunophil ins are the FK506 binding proteins (FKBPs). FKBPs of a relative molecular m ass higher than 40000 also display chaperone activity and are part of the m ultichaperone complex that Hsp90 forms with substrate proteins. Their funct ion in this chaperone complex is still enigmatic. To further characterize t he function of FKBP52 we want to analyze constructs of FKBP52-fragments. He re we describe a fast and effective three-step purification procedure for a fragment of FKBP52 with a relative molecular mass of 48000, termed FKBP52- 123, consisting of affinity chromatography, anion-exchange column and gel-p ermeation chromatography. A yield of 1 mg pure protein per gram of cells wa s achieved. (C) 2000 Elsevier Science BN. All rights reserved.