Abstract
October 25, 2006
4:30 pm, 700 Clark Hall
Cornell University Biophysics Colloquium

Signal Transduction in Photoreceptors: Time-Resolved Crystallographic Studies


Keith Moffat
Louis Block Professor of Biochemistry & Molecular Biology
Member, The Institute for Biophysical Dynamics and PI, BioCARS
The University of Chicago, 929 East 57th Street,
Chicago, Illinois 60637, USA
Website

Signaling photoreceptors may be classified by the nature of their chromophore (e.g. retinal, p-coumaric acid, FMN, FAD, bilin, heme), the nature of their initial photochemistry (isomerization, formation or rupture of a covalent bond, electron transfer), and the structures of their sensor (input) and effector (output) domains. How does absorption of a photon by the chromophore produce structural changes that propagate across the sensor domain? How are these transferred either inter- or intramolecularly to the sensor domain? How is the activity of the effector domain thereby modulated? Are there general principles of signal generation and transduction, or is each photoreceptor unique? In short, how does signaling work, at the atomic level?

Answers to these questions will eventually be derived from high resolution, static and sub-nanosecond, time-resolved, crystallographic studies of photoreceptors, using the brilliant, pulsed X-ray beams from synchrotron sources such as CHESS, APS, ESRF and their successors. Some initial approaches and results on blue-light and near red/red/far red-light photoreceptors will be presented.

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