Brian Zoltowski
Cornell University
Abstract:
The Neurospora crassa photoreceptor Vivid tunes blue-light responses and
modulates gating of the circadian clock. Crystal structures of
dark- and light-state Vivid reveal a LOV/PAS domain with an unusual
N-terminal cap region and a loop insertion that accommodates the flavin
cofactor. Photoinduced formation of a cystein-flavin adduct drives
flavin protonation to induce an N-terminal conformational change.
A cysteine-to-serine substitution remote from the FAD binding site
decouples conformational switching form the flavin photcycle and
prevents VVD from sending signals in Neuroses. Key elements of
this activation mechanism are conserved by other photosensors such as
White-Collar-1, Zeitlupe, ENVOY, and FKF1.
2008 Run
Nov 19th - Dec 22nd
