VISUALIZATION OF COHERENT NUCLEAR MOTION IN A MEMBRANE-PROTEIN BY FEMTOSECOND SPECTROSCOPY

Multicolour near-infrared femtosecond experiments of a genetically mod ified bacterial reaction centre show that the phase of two excited-sta te vibrational modes is conserved for a period of picoseconds over a l arge range of temperatures. The direct visualization of low-frequency nuclear vibrations in this protein, which is embedded in its natural m embrane, implicates coherent nuclear motion in the primary electron tr ansfer reaction in functional reaction centres.