Ground-state heterogeneity and vibrational energy redistribution in bacterial phytochrome observed with femtosecond 2D IR spectroscopy
Phytochromes belong to a group of photoreceptor proteins containing a covalently bound biliverdin chromophore that inter-converts between two isomeric forms upon photoexcitation. The existence and stability of the photocycle products are largely determined by the protein sequence and the presence of conserved hydrogen-bonding interactions in the vicinity of the chromophore. The vibrational signatu