Noncanonical Photocycle Initiation Dynamics of the Photoactive Yellow Protein (PYP) Domain of the PYP-Phytochrome-Related (Ppr) Photoreceptor

作者：Mix L Tyler; Hara Miwa; Rathod Rachana; Kumauchi Masato; Hoff Wouter D; Larsen Delmar S^*

来源：Journal of Physical Chemistry Letters, 2016, 7(24): 5212-5218.

DOI：10.1021/acs.jpclen.6b02253

The photoactive yellow protein (PYP) from Halorhodospira halophila (Hhal) is a bacterial photoreceptor and model system for exploring functional protein dynamics. We report ultrafast spectroscopy experiments that probe photocycle initiation dynamics in the PYP domain from the multidomain PYP-phytochrome-related photoreceptor from Rhodospirillum centenum (Rcen). As with Hhal PYP, Rcen PYP exhibits similar excited-state dynamics; in contrast, Rcen PYP exhibits altered photoproduct ground-state dynamics in which the primary I-0, intermediate as observed in Hhal PYP is absent. This property is attributed to a tighter, more sterically constrained binding pocket around the p-coumaric acid chromophore due to a change in the Rcen PYP protein structure that places Phe98 instead of Met100 in contact with the chromophore. Hence, the I-0 state is not a necessary step for the initiation of productive PYP photocycles and the ubiquitously studied Hhal PYP may not be representative of the broader PYP family of photodynamics.

• 出版日期2016-12-15