Structural characterization of a partly folded apomyoglobin intermediate.
To understand why proteins adopt particular three-dimensional structures, it is important to elucidate the hierarchy of interactions that stabilize the native state. Proteins in partly folded states can be used to dissect protein organizational hierarchies. A partly folded apomyoglobin intermediate has now been characterized structurally by trapping slowly exchanging peptide NH protons and analyzing them by two-dimensional 1H-NMR (nuclear magnetic resonance). Protons in the A, G, and H helix regions are protected from exchange, while protons in the B and E helix regions exchange freely. On the basis of these results and the three-dimensional structure of native myoglobin, a structural model is presented for the partly folded intermediate in which a compact subdomain retains structure while the remainder of the protein is essentially unfolded.
Hughson
F M
FM
Department of Biochemistry, Beckman Center, Stanford University School of Medicine, CA 94305.
Wright
P E
PE
Baldwin
R L
RL
D000595:Amino Acid Sequence; D001059:Apoproteins / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009211:Myoglobin / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet
D001059:Apoproteins; D009211:Myoglobin; C010857:apomyoglobin