Partially folded, molten globule and molten coil states of bovine pancreatic trypsin inhibitor.
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'.
Ferrer
M
M
Department of Chemistry, University of Minnesota, Minneapolis 55455, USA.
Barany
G
G
Woodward
C
C
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
D000817:Anilino Naphthalenesulfonates; D004220:Disulfides; D005456:Fluorescent Dyes; C027132:1-anilino-8-naphthalenesulfonate; D007611:Aprotinin