Curated Optogenetic Publication Database

Abstract: Light-sensitive proteins allow organisms to perceive and respond to their environment, and have diversified over billions of years. Among these, Light-Oxygen-Voltage (LOV) domains are widespread photosensors that control diverse physiological processes and are increasingly used in optogenetics. Yet, the evolutionary constraints that shaped their protein dynamics and thereby their functional diversity remain poorly resolved. Here we systematically characterize the dynamics of 21 natural LOV core domains, significantly extending the spectroscopically resolved catalog through the addition of 18 previously unstudied variants. Using time-resolved spectroscopy, we uncover an exceptional kinetic diversity spanning from picoseconds to days and identify distinct functional clusters within the LOV family. These clusters reflect evolutionary branching, including a divergence of ≈1.0 billion years between investigatedLOV variants from plants and ≈0.4 billion years of separation within one of these functional clusters. Individual variants with extreme photocycles emerge as promising anchor points for optogenetic applications, ranging from highly efficient adduct formation to ultrafast recovery. Beyond natural diversity, we introduce a LOV domain generated by artificial intelligence-guided protein design. Despite being sequentially remote from its maternal template, this variant retains core photocycle function while exhibiting unique biophysical properties, thereby occupying a new region on the biophysical landscape. Our work emphasizes how billions of years of evolution defined LOV protein dynamics, and how protein design can expand this repertoire, engineering next-generation optogenetic tools.

Abstract: Recently, re-purposing of cyanobacterial photoreceptors as optogentic actuators enabled light-regulated protein expression in different host systems. These new bi-stable optogenetic tools enable interesting new applications, but their light-driven working mechanism remains largely elusive on a molecular level. Here, we study the optogenetic cyanobacteriochrome Am1-c0023g2 with isotope labeling and two dimensional infrared (2D-IR) spectroscopy. Isotope labeling allows us to isolate two site-specific carbonyl marker modes from the overwhelming mid-IR signal of the peptide backbone vibrations. Unlike conventional difference-FTIR spectroscopy, 2D-IR is sensitive to homogeneous and inhomogeneous broadening mechanisms of these two vibrational probes in the different photostates of the protein. We analyse the 2D-IR line shapes in the context of available structural models and find that they reflect the hydrogen-bonding environment of these two marker groups.