Computational Design of artificial protein-photoreceptors for optogenetics applications

• Applicant: Florian Richter, Ph.D.
• Subject Area: Biophysics ; Biochemistry
• Term: from 2013 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 242850983

The aim of this proposal is to combine the emerging fields of computational protein design (CPD) and optogenetics. The subject of CPD is the design of proteins with new functions. Optogenerics describes the control of biological processes by light. Underlying all optogenetics applications are a class of light-sensitive proteins called photoreceptors. Current optogenetic applications generally rely on natural photoreceptors, and attempts at designing artificial photoreceptors have relied on simple design approaches. Artificial photoreceptors are usually inferior to their natural counterparts. By applying advanced computational methodology, in combination with high-throughput screening, we propose to extend optogenetics to target biological phenomena not accessible by current photoreceptor design approaches. Specifically, we propose to use CPD alongside a fluorescent-reporter based high-throughput assay to create a heterodimeric version of a naturally occurring, homodimeric photoreceptor. This designed heterodimeric photoreceptor can then be used to render the activity of other heterodimeric effector proteins (i.e. G-proteins or transcription factors) light-sensitive. In particular, we will target G-protein signaling by using CPD to create fusions between the designed heterodimeric photoreceptor and the heterodimeric G beta/gamma subunit, which plays a central role in G-protein signaling linked events. A yeast-display based selection scheme will be used to screen for fusions with light-dependent affinity for the Galpha subunit. If successful, this would lay the groundwork for triggering signaling processes in mammalian cells by light.

• DFG Programme: Research Grants