Structure and vibrational dynamics of model compounds of the [FeFe]-hydrogenase enzyme system via ultrafast two-dimensional infrared spectroscopy

J Phys Chem B. 2008 Aug 14;112(32):10023-32. doi: 10.1021/jp803338d. Epub 2008 Jul 23.

Abstract

Ultrafast two-dimensional infrared (2D) spectroscopy has been applied to study the structure and vibrational dynamics of (mu-S(CH2)3S)Fe2(CO)6, a model compound of the active site of the [FeFe]-hydrogenase enzyme system. Comparison of 2D-IR spectra of (mu-S(CH2)3S)Fe2(CO)6 with density functional theory calculations has determined that the solution-phase structure of this molecule is similar to that observed in the crystalline phase and in good agreement with gas-phase simulations. In addition, vibrational coupling and rapid (<5 ps) solvent-mediated equilibration of energy between vibrationally excited states of the carbonyl ligands of the di-iron-based active site model are observed prior to slower (approximately 100 ps) relaxation to the ground state. These dynamics are shown to be solvent-dependent and form a basis for the future determination of the vibrational interactions between active site and protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Hydrogenase / chemistry
  • Hydrogenase / metabolism*
  • Iron-Sulfur Proteins / chemistry
  • Iron-Sulfur Proteins / metabolism*
  • Spectrophotometry, Infrared / methods*

Substances

  • Iron-Sulfur Proteins
  • iron hydrogenase
  • Hydrogenase