Open AccessPump–Probe Circular Dichroism Spectroscopy of Cyanobacteriochrome TePixJ Yields: Insights into Its Photoconversion
Author(s) -
J.A. Clinger,
Eefei Chen,
David S. Kliger,
George N. Phillips
Publication year - 2020
Publication title -
the journal of physical chemistry. b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 392
eISSN - 1520-6106
pISSN - 1520-5207
DOI - 10.1021/acs.jpcb.0c04822
Subject(s) - circular dichroism , phototaxis , absorption (acoustics) , spectroscopy , phytochrome , chemistry , photochemistry , optics , crystallography , physics , red light , biology , botany , quantum mechanics
The bilin-containing photoreceptor TePixJ, a member of the cyanobacteriochrome (CBCR) family of phytochromes, switches between blue-light-absorbing and green-light-absorbing states in order to drive phototaxis in Thermosynechococcus elongatus . Its photoswitching process involves the formation of a thioether linkage between the C10 carbon of phycoviolobilin and the sidechain of Cys494 during the change in state from green-absorbing to blue-absorbing forms. Complex changes in the binding pocket propagate the signal to other domains for downstream signaling. Here, we report time-resolved circular dichroism experiments in addition to pump-probe absorption measurements for interpretation of the biophysical mechanism of the green-to-blue photoconversion process of this receptor.