Patent ID: 7125696

Claim:
A method for preparing a purified solution of polypeptide soluble in aqueous solvent in the absence of detergent, from a purified solution of a polypeptide containing detergent, said polypeptide being a Klebsiella pneumoniae membrane protein OmpA having the sequence of SEQ ID No. 2 which method comprises the following steps: a. removing the detergent from the purified solution containing a detergent; b. solubilizing the polypeptide obtained in step a) in a solution containing a denaturing agent selected from the group consisting of urea and guanidine hydrochloride; and c. eluting in aqueous medium the polypeptide solubilized in step b), by molecular sieving on a chromatography column; whereby a tertiary structure of the polypeptide which is a β-sheet type is modified to an α-helix type.