High populations of non-native structures in the denatured state are compatible with the formation of the native folded state.
The structures of the denatured states of the spectrin SH3 domain and a mutant designed to have a non-native helical tendency at the N terminus have been analyzed under mild acidic denaturing conditions by nuclear magnetic resonance methods with improved resolution. The wild-type denatured state has little residual structure. However, the denatured state of the mutant has an approximately 50% populated helical structure from residues 2 to 14, a region that forms part of the beta-sheet structure in the folded state. Comparison with a peptide corresponding to the same sequence shows that the helix is stabilized in the whole domain, likely by non-local interactions with other parts of the protein as suggested by changes in a region far from the mutated sequence. These results demonstrate that high populations of non-native secondary structure elements in the denatured state are compatible with the formation of the native folded structure.
Blanco
F J
FJ
EMBL, Meyerhofstrasse 1, Heidelberg, D69012, Germany.
Serrano
L
L
Forman-Kay
J D
JD
D000595:Amino Acid Sequence; D004355:Drug Stability; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013049:Spectrin / Q000737:chemistry* / Q000235:genetics; D018909:src Homology Domains
D010446:Peptide Fragments; D013049:Spectrin