Watching a Protein as it Functions with 150-ps Time-Resolved X-ray Crystallography

• DOI: 10.1126/science.1078797
• Publication Date: 2003-06-19T21:15:28Z
• Authors: Friedrich Schotte; Manho Lim; Timothy A. Jackson; Aleksandr V. Smirnov; Jayashree Soman; John S. Olson; George N. Phillips; Michael Wulff; Philip A. Anfinrud
• Keywords: Picosecond; Angstrom; Protein Dynamics

We report picosecond time-resolved x-ray diffraction from the myoglobin (Mb) mutant in which Leu 29 is replaced by Phe (L29Fmutant). The frame-by-frame structural evolution, resolved to 1.8 angstroms, allows one literally “watch” protein as it executes its function. Time-resolved mid-infrared spectroscopy of flash-photolyzed L29F MbCO revealed a short-lived CO intermediate whose 140-ps lifetime shorter than that found wild-type factor 1000. electron density maps unveil transient conformational changes far more dramatic differences between carboxy and deoxy states depict correlated side-chain motion responsible for rapidly sweeping away primary docking site.