title: Properties of the dark and signaling states of photoactive yellow protein probed by solution phase hydrogen/deuterium exchange and mass spectrometry.
abstract: The perturbations on conversion from the dark state to the signaling state in photoactive yellow protein have been determined by solution-phase hydrogen/deuterium exchange and mass spectrometry. Both the wild type and M100A mutant are used in this study, with the mutant providing over 90% conversion to the bleached state under steady-state illumination. We found perturbations in both the wild type and the mutant on illumination, consistent with a more flexible structure in the long-lived signaling (I2') state. In the case of the wild type, the conformational changes detected are mainly around the chromophore region. With the M100A mutant, differences in H/D exchange between the light and dark are more extensive as compared to wild type; not only are the chromophore surroundings affected, but significant increases in deuterium uptake in the N-terminus and central beta-sheet are observed as well. On the basis of the data obtained from this study and previous findings, a sequence of events that leads to the perturbation of PYP following chromophore photoisomerization is proposed.
authors.affiliation: Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: Guilong
authors.initials: G
authors.lastname: Cheng
authors.forename: Michael A
authors.initials: MA
authors.lastname: Cusanovich
authors.forename: Vicki H
authors.initials: VH
authors.lastname: Wysocki
mesh_terms: D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003903:Deuterium / Q000737:chemistry*; D020607:Halorhodospira halophila / Q000737:chemistry* / Q000502:physiology; D007536:Isomerism; D008958:Models, Molecular; D020125:Mutation, Missense; D020283:Photoreceptors, Microbial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D015398:Signal Transduction; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; C050162:photoactive yellow protein, Bacteria; D003903:Deuterium