Formation of a molten globule intermediate early in the kinetic folding pathway of apomyoglobin.
Hydrogen exchange pulse labeling and stopped-flow circular dichroism were used to establish that the structure of the earliest detectable intermediate formed during refolding of apomyoglobin corresponds closely to that of a previously characterized equilibrium molten globule. This compact, cooperatively folded intermediate was formed in less than 5 milliseconds and contained stable, hydrogen-bonded secondary structure localized in the A, G, and H helices and part of the B helix. The remainder of the B helix folded on a much slower time scale, followed by the C and E helices and the CD loop. The data indicate that a molten globule intermediate was formed on the kinetic folding pathway.
Jennings
P A
PA
Department of Molecular Biology, Scripps Research Institute, La Jolla, California 92037.
Wright
P E
PE
D001059:Apoproteins / Q000737:chemistry*; D002942:Circular Dichroism; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009211:Myoglobin / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary
D001059:Apoproteins; D009211:Myoglobin; C010857:apomyoglobin; D006859:Hydrogen