On the (un)coupling of the chromophore, tongue interactions, and overall conformation in a bacterial phytochrome.

ABSTRACT: Phytochromes are photoreceptors in plants, fungi, and various microorganisms and cycle between metastable red light-absorbing (Pr) and far-red light-absorbing (Pfr) states. Their light responses are thought to follow a conserved structural mechanism that is triggered by isomerization of the chromophore. Downstream structural changes involve refolding of the so-called tongue extension of the phytochrome-specific GAF-related (PHY) domain of the photoreceptor. The tongue is connected to the chromophore by conserved DIP and PRXSF motifs and a conserved tyrosine, but the role of these residues in signal transduction is not clear. Here, we examine the tongue interactions and their interplay with the chromophore by substituting the conserved tyrosine (Tyr²⁶³) in the phytochrome

SUBMITTER: Takala H 

PROVIDER: S-EPMC5971452 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature