Hoff Research Summary
We use photoreceptor proteins as model systems for studying protein folding, function, and signaling, and have started to explore biotechnological applications for these proteins. Our long-term goal is to uncover fundamental principles in these processes, and to develop biosensors with useful applications. This research uses a wide range of approaches, from genomic studies to molecular genetics, protein biochemistry, protein spectroscopy and biophysics. We discovered that the activation of photoactive yellow protein (PYP), a bacterial blue-light receptor from the halophilic purple sulfur bacterium Halorhodopsira halophila, involves partial unfolding, providing an unexpected link between signaling and protein folding. We are analyzing the genome and halophilic adaptations of H. halophila, and are using genomic approaches to identify the signal transduction chain associated with PYP. We use infrared spectroscopy and other spectroscopic measurements to unravel the fundamental mechanisms in the activation of PYP and have developed novel high-throughput protein biophysics approaches. Our single-molecule force spectroscopy measurements allow us to apply a force to unfold the protein along a specific axis, determined by the position of introduced Cys residues. In addition, we are developing novel highly sensitive, specific, and fast biodetection devices based on engineered proteins that allow a direct optical readout.