Thermal unfolding of unsolvated cytochrome c: Experiment and molecular dynamics simulations

Yi Mao, Jürgen Woenckhaus, Jiri Kolafa, Mark A. Ratner, Martin F. Jarrold

Research output: Contribution to journalArticle

90 Citations (Scopus)

Abstract

The thermal unfolding of unsolvated cytochrome c has been examined in the gas phase using ionmobility measurements. Measurements were performed for the +5, +6, and +7 protonated charge states from around room temperature up to 573 K. The (M + 5H)5+ charge state remains folded at 573 K while (M + 6H)6+ and (M + 7H)7+ go through a series of unfolding transitions as the temperature is raised. Molecular dynamics simulations were performed using the CHARMM force field. The simulations are in qualitative agreement with the experimental results: the +7 charge states unfold as the temperature is raised and the +5 charge states remain compact. Addition of two protons to the +5 charge state flattens the energy landscape so that the folded and unfolded conformations have similar energies. Entropy presumably drives the unfolding of the +7 charge state as the temperature is raised.

Original languageEnglish
Pages (from-to)2712-2721
Number of pages10
JournalJournal of the American Chemical Society
Volume121
Issue number12
DOIs
Publication statusPublished - Mar 31 1999

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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