Transducer Binding Establishes Localized Interactions to Tune Sensory Rhodopsin II

David A. Cisneros, Leoni Oberbarnscheidt, Angela Pannier, Johann P. Klare, Jonne Helenius, Martin Engelhard, Filipp Oesterhelt, Daniel J. Muller

Research output: Contribution to journalArticle

27 Scopus citations


In haloarchaea, sensory rhodopsin II (SRII) mediates a photophobic response to avoid photo-oxidative damage in bright light. Upon light activation the receptor undergoes a conformational change that activates a tightly bound transducer molecule (HtrII), which in turn by a chain of homologous reactions transmits the signal to the chemotactic eubacterial two-component system. Here, using single-molecule force spectroscopy, we localize and quantify changes to the intramolecular interactions within SRII of Natronomonas pharaonis (NpSRII) upon NpHtrII binding. Transducer binding affected the interactions at transmembrane α helices F and G of NpSRII to which the transducer was in contact. Remarkably, the interactions were distributed asymmetrically and significantly stabilized α helix G entirely but α helix F only at its extracellular tip. These findings provide unique insights into molecular mechanisms that "prime" the complex for signaling, and guide the receptor toward transmitting light-activated structural changes to its cognate transducer.

Original languageEnglish (US)
Pages (from-to)1206-1213
Number of pages8
Issue number8
Publication statusPublished - Aug 6 2008




ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

Cite this

Cisneros, D. A., Oberbarnscheidt, L., Pannier, A., Klare, J. P., Helenius, J., Engelhard, M., ... Muller, D. J. (2008). Transducer Binding Establishes Localized Interactions to Tune Sensory Rhodopsin II. Structure, 16(8), 1206-1213.