title: Packing interactions in the apomyglobin folding intermediate.
abstract: The contribution of specific packing to the stability of the sperm whale apomyoglobin intermediate has been studied by urea denaturation monitored by circular dichroism and fluorescence. Mutations disrupting native packing sites within the subdomain formed by the A, G and H helices destabilize the intermediate, in contrast to the conclusion drawn from earlier studies of pH-induced unfolding. Based on these results, the intermediate is proposed to be stabilized by both partially formed native-like tertiary, and non-specific hydrophobic interactions forming a subdomain folding intermediate. The results help to explain how the intermediate acquires its structure and stability.
authors.affiliation: Department of Biochemistry, Stanford University Medical Center, California 94305-5307, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Kay
authors.forename: R L
authors.initials: RL
authors.lastname: Baldwin
mesh_terms: D000143:Acids / Q000494:pharmacology; D001059:Apoproteins / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D002942:Circular Dichroism; D003198:Computer Simulation; D008956:Models, Chemical; D009154:Mutation; D009211:Myoglobin / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D011487:Protein Conformation / Q000187:drug effects; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence; D014508:Urea / Q000494:pharmacology
chemical_list: D000143:Acids; D001059:Apoproteins; D009211:Myoglobin; C010857:apomyoglobin; D014508:Urea