title: Partially folded, molten globule and molten coil states of bovine pancreatic trypsin inhibitor.
abstract: Three denatured states of bovine pancreatic trypsin inhibitor have been characterized, using two chemically synthesized analogues designed for study of folding intermediates. One analogue, [14-38]Abu, retains only the 14-38 disulphide. At pH 4.5-6 and 1-7 degrees C, [14-38]Abu is a highly ordered beta-sheet molten globule; it has the circular dichroism (CD), ANS-binding and folding kinetics of a molten globule; is partially folded by NMR analysis; and undergoes cooperative thermal denaturation. At low temperature [14-38]Abu also forms an acid state at pH 1.5, as well as a denatured state at pH 2.5. A second BPTI analogue with all three disulphide bridges eliminated, [R]Abu, lacks detectable secondary and tertiary structure but has stable hydrophobic surfaces and is collapsed. We term this species a 'molten coil'.
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis 55455, USA.
authors.forename: M
authors.initials: M
authors.lastname: Ferrer
authors.forename: G
authors.initials: G
authors.lastname: Barany
authors.forename: C
authors.initials: C
authors.lastname: Woodward
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D000818:Animals; D007611:Aprotinin / Q000031:analogs & derivatives / Q000737:chemistry* / Q000378:metabolism; D002417:Cattle; D002942:Circular Dichroism; D004220:Disulfides / Q000737:chemistry; D005456:Fluorescent Dyes / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D011485:Protein Binding; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013050:Spectrometry, Fluorescence
chemical_list: D000817:Anilino Naphthalenesulfonates; D004220:Disulfides; D005456:Fluorescent Dyes; C027132:1-anilino-8-naphthalenesulfonate; D007611:Aprotinin