title: Long-range interactions within a nonnative protein.
abstract: Protein folding and unfolding are coupled to a range of biological phenomena, from the regulation of cellular activity to the onset of neurodegenerative diseases. Defining the nature of the conformations sampled in nonnative proteins is crucial for understanding the origins of such phenomena. We have used a combination of nuclear magnetic resonance (NMR) spectroscopy and site-directed mutagenesis to study unfolded states of the protein lysozyme. Extensive clusters of hydrophobic structure exist within the wild-type protein even under strongly denaturing conditions. These clusters involve distinct regions of the sequence but are all disrupted by a single point mutation that replaced residue Trp62 with Gly located at the interface of the two major structural domains in the native state. Thus, nativelike structure in the denatured protein is stabilized by the involvement of Trp62 in nonnative and long-range interactions.
authors.affiliation: Massachusetts Institute of Technology, Department of Chemistry, Francis Bitter Magnet Laboratory, 170 Albany Street, Cambridge, MA 02139, USA.
authors.forename: Judith
authors.initials: J
authors.lastname: Klein-Seetharaman
authors.forename: Maki
authors.initials: M
authors.lastname: Oikawa
authors.forename: Shaun B
authors.initials: SB
authors.lastname: Grimshaw
authors.forename: Julia
authors.initials: J
authors.lastname: Wirmer
authors.forename: Elke
authors.initials: E
authors.lastname: Duchardt
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ueda
authors.forename: Taiji
authors.initials: T
authors.lastname: Imoto
authors.forename: Lorna J
authors.initials: LJ
authors.lastname: Smith
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Dobson
authors.forename: Harald
authors.initials: H
authors.lastname: Schwalbe
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002645:Chickens; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry; D005998:Glycine / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D009113:Muramidase / Q000737:chemistry* / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D017354:Point Mutation; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D014364:Tryptophan / Q000737:chemistry
chemical_list: D004220:Disulfides; D014364:Tryptophan; C421864:hen egg lysozyme; D009113:Muramidase; D003545:Cysteine; D005998:Glycine