title: Equilibrium folding of porcine insulin precursor in the presence of redox buffer: implications for the common intermediates shared by its unfolding/ refolding processes.
abstract: We use the procedure established for 'disulfide stability analysis in redox system' to investigate the unfolding process of porcine insulin precursor (PIP). Six major unfolding intermediates have been captured, in which four contain two disulfides, two contain one disulfide. Based on the characterization and analysis of the intermediates an unfolding pathway has been proposed, by which the native PIP unfolded through in turn 2SS and 1SS intermediates into fully reduced form. Besides, the comparison of the intermediates captured in PIP unfolding process with those intermediates captured in its refolding process revealed that some intermediates captured during both unfolding/refolding processes of PIP have identical disulfide pairing pattern, from which we suggest that the unfolding/refolding processes of PIP share some common intermediates but flow in the opposite direction.
authors.affiliation: College of Life Science, Zhejiang Sci-Tech University, Hangzhou 310018, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.forename: Qi-Long
authors.initials: QL
authors.lastname: Huang
authors.forename: Yue-Hua
authors.initials: YH
authors.lastname: Tang
authors.forename: Zhan-Yun
authors.initials: ZY
authors.lastname: Guo
authors.forename: Zhi-Song
authors.initials: ZS
authors.lastname: Qiao
authors.forename: Gen-Jun
authors.initials: GJ
authors.lastname: Xu
authors.forename: You-Min
authors.initials: YM
authors.lastname: Feng
mesh_terms: D000818:Animals; D002021:Buffers; D002851:Chromatography, High Pressure Liquid; D005978:Glutathione; D019803:Glutathione Disulfide; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D011384:Proinsulin / Q000737:chemistry* / Q000302:isolation & purification; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D013552:Swine
chemical_list: D002021:Buffers; D011994:Recombinant Proteins; D011384:Proinsulin; D005978:Glutathione; D019803:Glutathione Disulfide