PURIFICATION AND CHARACTERIZATION OF HUMAN PANCREATIC-POLYPEPTIDE EXPRESSED IN ESCHERICHIA-COLI

The region of cDNA encoding human pancreatic polypeptide (hPP) was obt ained by polymerase chain reaction (PCR) and subcloned into an express ion vector. The pancreatic polypeptide gene was expressed in Escherich ia coli in two versions: as a cleavable fusion protein with IgG-bindin g synthetic ZZ domains of protein A from Staphylococcus aureus or with the 1-48 fragment of lambda Cro repressor, Site-specific hydrolysis b y hydroxylamine was used to cleave the fusion protein, releasing the h uman polypeptide. The structure of the obtained hPP has been studied b y scanning microcalorimetry and circular dichroism spectrometry. It ha s been shown that hPP in solutions close to neutral has a compact and unique spatial structure with an extended hydrophobic core. This struc ture is stable at 20 degrees C and co-operatively breaks down upon hea ting from this temperature. (C) 1995 Academic Press, Inc.