A structural pathway for signaling in the E46Q mutant of photoactive yellow protein.


In the bacterial photoreceptor photoactive yellow protein (PYP), absorption of blue light by its chromophore leads to a conformational change in the protein associated with differential signaling activity, as it executes a reversible photocycle. Time-resolved Laue crystallography allows structural snapshots (as short as 150 ps) of high crystallographic resolution (approximately 1.6 A) to be taken of a protein as it functions. Here, we analyze by singular value decomposition a comprehensive time-resolved crystallographic data set of the E46Q mutant of PYP throughout the photocycle spanning 10 ns-100 ms. We identify and refine the structures of five distinct intermediates and provide a plausible chemical kinetic mechanism for their inter conversion. A clear structural progression is visible in these intermediates, in which a signal generated at the chromophore propagates through a distinct structural pathway of conserved residues and results in structural changes near the N terminus, over 20 A distant from the chromophore.

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@article{Rajagopal2005ASP, title={A structural pathway for signaling in the E46Q mutant of photoactive yellow protein.}, author={Sudarshan Rajagopal and Spencer M Anderson and Vukica {\vS}rajer and Marius Schmidt and Reinhard Pahl and Keith R. Moffat}, journal={Structure}, year={2005}, volume={13 1}, pages={55-63} }