Download MendeleyProtein kinetics: Structures of intermediates and reaction mechanism from time-resolved x-ray data
Schmidt, M., Pahl, R., Srajer, V., Anderson, S., Ren, Z., Ihee, H., Rajagopal, S., Moffat, K.(2004) Proc Natl Acad Sci U S A 101: 4799-4804
- PubMed: 15041745
- DOI: https://doi.org/10.1073/pnas.0305983101
- Primary Citation of Related Structures:
1S4R, 1S4S - PubMed Abstract:
We determine the number of authentic reaction intermediates in the later stages of the photocycle of photoactive yellow protein at room temperature, their atomic structures, and a consistent set of chemical kinetic mechanisms, by analysis of a set of time-dependent difference electron density maps spanning the time range from 5 micros to 100 ms. The successful fit of exponentials to right singular vectors derived from a singular value decomposition of the difference maps demonstrates that a chemical kinetic mechanism holds and that structurally distinct intermediates exist. We identify two time-independent difference maps, from which we refine the structures of the corresponding intermediates. We thus demonstrate how structures associated with intermediate states can be extracted from the experimental, time-dependent crystallographic data. Stoichiometric and structural constraints allow the exclusion of one kinetic mechanism proposed for the photocycle but retain other plausible candidate kinetic mechanisms.
Organizational Affiliation:
Physikdepartment E17, Technische Universität München, 85747 Garching, Germany. marius@hexa.e17.physik.tu-muenchen.de
