title: Investigating the refolding pathway of human acidic fibroblast growth factor (hFGF-1) from the residual structure(s) obtained by denatured-state hydrogen/deuterium exchange.
abstract: Human fibroblast growth factor 1 (hFGF-1) consists of 12 anti-parallel β-strands arranged into a β-trefoil architecture. We directly measured hydrogen/deuterium exchange rates on the urea-denatured hFGF-1 to obtain the information with regard to the persistent residual interaction(s) in the unfolded hFGF-1. Thirty-eight residues whose heteronuclear single quantum coherence cross-peaks can be observed after exchange show higher protections than those predicted for the same residues in a random coil conformation, suggesting the existence of residual structure(s). The urea-denaturation of hFGF-1 tested by both circular dichroism and fluorescence spectroscopy indicated that the unfolding process is a cooperative two-state process and that the residual structures observed did not originate from the existence of a partially structured intermediate. The coincident disappearance of the native heteronuclear single quantum coherence cross-peaks during the urea-denaturation process suggests that the residual structures observed contain no nativelike interactions. The protected residues (fold ons) in the urea-denatured state are mostly those that exchange slowly in the native state H/D exchange. The distribution of these fold ons in the native structure of hFGF-1 suggests that the refolding starts by collisions between the residual structures (microdomains) between the β-strands VI and VII, and between the β-strands II and III, which appear to be two independent refolding coordinates during the refolding process.
authors.affiliation: Department of Chemistry, National Tsing-Hua University, Hsin-Chu, Taiwan, Republic of China.
authors.forename: Han-Min
authors.initials: HM
authors.lastname: Wang
authors.forename: Chin
authors.initials: C
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism*; D041961:Deuterium Exchange Measurement / Q000379:methods*; D016220:Fibroblast Growth Factor 1 / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D006860:Hydrogen Bonding / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011489:Protein Denaturation / Q000187:drug effects; D058849:Protein Refolding / Q000187:drug effects; D017433:Protein Structure, Secondary; D058767:Protein Unfolding / Q000187:drug effects; D014508:Urea / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D016220:Fibroblast Growth Factor 1; D014508:Urea