Long-range interactions within a nonnative protein.
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.
Klein-Seetharaman
Judith
J
Massachusetts Institute of Technology, Department of Chemistry, Francis Bitter Magnet Laboratory, 170 Albany Street, Cambridge, MA 02139, USA.
Oikawa
Maki
M
Grimshaw
Shaun B
SB
Wirmer
Julia
J
Duchardt
Elke
E
Ueda
Tadashi
T
Imoto
Taiji
T
Smith
Lorna J
LJ
Dobson
Christopher M
CM
Schwalbe
Harald
H
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
D004220:Disulfides; D014364:Tryptophan; C421864:hen egg lysozyme; D009113:Muramidase; D003545:Cysteine; D005998:Glycine