Formation of a molten globule intermediate early in the kinetic folding pathway of apomyoglobin

Science. 1993 Nov 5;262(5135):892-6. doi: 10.1126/science.8235610.

Abstract

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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Apoproteins / chemistry*
  • Circular Dichroism
  • Hydrogen / chemistry
  • Hydrogen Bonding
  • Kinetics
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Myoglobin / chemistry*
  • Protein Conformation*
  • Protein Folding*
  • Protein Structure, Secondary

Substances

  • Apoproteins
  • Myoglobin
  • apomyoglobin
  • Hydrogen