Characterization of longe-range signal transduction in red-light activated diguanylyl cyclases

Geoffrey Simon Gourinchas, Stefan Etzl, Andreas Winkler

Research output: Contribution to conferencePoster


Organisms that benefit from lightas energy source have developed complex protein architectures enablingadaptation to their light environments. Photo-perception is allowed by acollection of modular photoreceptors that couple light sensing to signalingcascades critical for cell survival. Recently, photosensory domains coupled toenzymatic effectors have attracted special attention due to their potential foroptogenetic applications [1]. Among them, red-light activated phytochromes areparticularly promising due to deep-tissue penetration and low phototoxicity ofred-light. However, the limited understanding of molecular mechanisms of light-signaltransduction limits the rational design of innovative sensor-effector couples.

Naturallyoccurring red-light activated diguanylyl cyclases (PadC) are constituted of acanonical bacteriophytochrome [2], able to photointerconvert between aninactive state (Pr) and an active conformation (Pfr) by red- light illuminationleading to isomerization of its biliverdin chromophore. The photosensory moduleis fused to a GGDEF domain [3] featuring diguanylyl cyclase activity, which is involvedin synthesis of the bacterial second messenger bis-(3′-5′) cyclic-dimeric-GMP.

Using biochemicaland biophysical methods we obtained structural details of a full-length PadC inthe Pr-state that supports the involvement of previously proposed importantstructural elements of phytochrome signaling [4]. Moreover, we highlight theimportance of the sensor-effector linker element and show that its composition isfine-tuned for enabling the conformational dynamics required for signaltransduction. Currently we are addressing structural details of the Pfr state toimprove our understanding of molecular mechanisms involved in communication betweenthe phytochrome, the sensor-effector linker and the functional output domain.


Acknowledgements:This project has been initiated with a startup financing grant by GrazUniversity of Technology (F-AF5-648-01). A.W. acknowledges funding by theAustrian Science fund (FWF): P27124. G.G. and S.E. are supported by theAustrian Science Fund through the PhD programme “DK Molecular Enzymology”(W901).



[1] D. Tischer & O. Weiner:Illuminating cell signalling with optogenetic tools. Nat. Rev. Mol. CellBiol. 15 (2014)551-558.

[2] K. Anders & L. Essen: Thefamily of phytochrome-like photoreceptors: diverse, complex and multi-colored,but very useful. Curr. Opin. Struct. Biol. 35 (2015) 7-16.

[3] D. Ryjenkov, M. Tarutina, O.Moskvin & M. Gomelsky: Cyclic diguanylate is a ubiquitous signalingmolecule in bacteria: insights into biochemistry of the GGDEF protein domain. JBacteriol 187 (2005)1792-8.

[4] E. Burgie & R. Vierstra: Phytochromes:An Atomic Perspective on Photoactivation and Signaling. Plant Cell 26 (2014) 4568-4583.

Original languageEnglish
Publication statusPublished - 27 Jun 2016
EventFEBS Advanced Methods in Macromolecular Crystallization VII - Nové Hrady, Czech Republic
Duration: 27 Jun 20162 Jul 2016


ConferenceFEBS Advanced Methods in Macromolecular Crystallization VII
Country/TerritoryCzech Republic
CityNové Hrady


  • Structural biology
  • crystallization

Fields of Expertise

  • Human- & Biotechnology

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