The structural effect between the output module and chromophore-binding domain is a two-way street via the hairpin extension

Moona Kurttila, Stefan Etzl, Jessica Rumfeldt, Heikki Takala, Nadine Galler, Andreas Winkler*, Janne A Ihalainen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Signal transduction typically starts with either ligand binding or cofactor activation, eventually affecting biological activities in the cell. In red light-sensing phytochromes, isomerization of the bilin chromophore results in regulation of the activity of diverse output modules. During this process, several structural elements and chemical events influence signal propagation. In our study, we have studied the full-length bacteriophytochrome from Deinococcus radiodurans as well as a previously generated optogenetic tool where the native histidine kinase output module has been replaced with an adenylate cyclase. We show that the composition of the output module influences the stability of the hairpin extension. The hairpin, often referred as the PHY tongue, is one of the central structural elements for signal transduction. It extends from a distinct domain establishing close contacts with the chromophore binding site. If the coupling between these interactions is disrupted, the dynamic range of the enzymatic regulation is reduced. Our study highlights the complex conformational properties of the hairpin extension as a bidirectional link between the chromophore-binding site and the output module, as well as functional properties of diverse output modules.

Original languageEnglish
Number of pages14
JournalPhotochemical & photobiological sciences
Early online date19 Aug 2022
DOIs
Publication statusE-pub ahead of print - 19 Aug 2022

Keywords

  • Photoreceptor
  • Bacteriophytochrome
  • Sensor-Effector Modularity

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Fields of Expertise

  • Human- & Biotechnology

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