Quantum chemical calculations of [NiFe] hydrogenase.

During the past five years, the metalloenzyme [NiFe] hydrogenase has increasingly attracted the interest of quantum chemists. In particular, different approaches have been applied to investigate the mechanism of the heterolytic splitting of molecular hydrogen. These theoretical studies have stimulated many new questions rather than given final answers. It has recently become possible to directly calculate experimental observables from first principles. Here, it is demonstrated how vibrational frequencies, g-values and hyperfine coupling constants (for Fourier-transformed infrared spectroscopy and electron paramagnetic resonance spectroscopy) can be obtained, which allow a direct comparison with experimental data.