title: Mapping long-range contacts in a highly unfolded protein.
abstract: Insights into the earliest events in protein folding can be obtained by analysis of the conformational propensities of unfolded or partly folded states. The structure of the acid-unfolded state of apomyoglobin has been characterized using paramagnetic spin labeling and NMR. Nitroxide side-chains, introduced by coupling to mutant cysteine residues at positions 18, 77, and 133, were used as probes of chain compaction and long-range tertiary contacts. Significant interactions are observed within and between the N and C termini, while the central region of the polypeptide chain behaves as a random polymer. Even in this highly denatured form, the protein samples transient compact states in which there are native-like contacts between the N and C-terminal regions.
authors.affiliation: Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Lietzow
authors.forename: Marc
authors.initials: M
authors.lastname: Jamin
authors.forename: H Jane
authors.initials: HJ
authors.lastname: Dyson
authors.forename: Peter E
authors.initials: PE
authors.lastname: Wright
mesh_terms: D001059:Apoproteins / Q000737:chemistry* / Q000235:genetics; D016296:Mutagenesis; D009211:Myoglobin / Q000737:chemistry* / Q000235:genetics; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D013113:Spin Labels
chemical_list: D001059:Apoproteins; D009211:Myoglobin; D013113:Spin Labels; C010857:apomyoglobin