title: Relationship between chain collapse and secondary structure formation in a partially folded protein.
abstract: Chain collapse and secondary structure formation are frequently observed during the early stages of protein folding. Is the chain collapse brought about by interactions between secondary structure units or is it due to polymer behavior in a poor solvent (coil-globule transition)? To answer this question, we measured small-angle X-ray scattering for a series of β-lactoglobulin mutants under conditions in which they assume a partially folded state analogous to the folding intermediates. Mutants that were designed to disrupt the secondary structure units showed the gyration radii similar to that of the wild type protein, indicating that chain collapse is due to coil-globule transitions.
authors.affiliation: Department of Bioinformatics, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo, 192-8577, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Yamada
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Matsumura
authors.forename: Seiichi
authors.initials: S
authors.lastname: Tsukamoto
authors.forename: Mio
authors.initials: M
authors.lastname: Yamamoto-Ohtomo
authors.forename: Hideaki
authors.initials: H
authors.lastname: Ohtomo
authors.forename: Takahiro
authors.initials: T
authors.lastname: Okabe
authors.forename: Kazuo
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Masamichi
authors.initials: M
authors.lastname: Ikeguchi
mesh_terms: D000818:Animals; D002942:Circular Dichroism; D006736:Horses; D007782:Lactoglobulins / Q000737:chemistry* / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D011392:Proline / Q000235:genetics; D017510:Protein Folding; D017433:Protein Structure, Secondary
chemical_list: D007782:Lactoglobulins; D011392:Proline
keywords: cold denaturation; electrostatic repulsion; molten globule; protein folding; small-angle X-ray scattering