title: The kinetic dose limit in room-temperature time-resolved macromolecular crystallography.
abstract: Protein X-ray structures are determined with ionizing radiation that damages the protein at high X-ray doses. As a result, diffraction patterns deteriorate with the increased absorbed dose. Several strategies such as sample freezing or scavenging of X-ray-generated free radicals are currently employed to minimize this damage. However, little is known about how the absorbed X-ray dose affects time-resolved Laue data collected at physiological temperatures where the protein is fully functional in the crystal, and how the kinetic analysis of such data depends on the absorbed dose. Here, direct evidence for the impact of radiation damage on the function of a protein is presented using time-resolved macromolecular crystallography. The effect of radiation damage on the kinetic analysis of time-resolved X-ray data is also explored.
authors.affiliation: Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA. m-schmidt@uwm.edu
authors.forename: M
authors.initials: M
authors.lastname: Schmidt
authors.forename: V
authors.initials: V
authors.lastname: Šrajer
authors.forename: N
authors.initials: N
authors.lastname: Purwar
authors.forename: S
authors.initials: S
authors.lastname: Tripathi
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000528:radiation effects*; D018360:Crystallography, X-Ray; D007700:Kinetics; D046911:Macromolecular Substances / Q000737:chemistry; D055641:Mathematical Concepts; D020283:Photoreceptors, Microbial / Q000737:chemistry* / Q000528:radiation effects*; D011506:Proteins / Q000737:chemistry / Q000528:radiation effects*; D013696:Temperature; D014965:X-Rays
chemical_list: D001426:Bacterial Proteins; D046911:Macromolecular Substances; D020283:Photoreceptors, Microbial; D011506:Proteins; C050162:photoactive yellow protein, Bacteria