Photoprotection is essential for efficient photosynthesis. Cyanobacteria have evolved a unique photoprotective mechanism mediated by a water-soluble carotenoid-based photoreceptor known as orange carotenoid protein (OCP). OCP undergoes large conformational changes in response to intense blue light, and the photoactivated OCP facilitates dissipation of excess energy via direct interaction with allophycocyanins at the phycobilisome core. I will present our recent work that shows direct observations of light-induced structural changes in OCP captured by dynamic crystallography. Difference electron densities between the dark and illuminated states reveal widespread and concerted atomic motions that lead to altered protein–pigment interactions, displacement of secondary structures, and domain separation. Based on these crystallographic observations together with site-directed mutagenesis, we propose a molecular mechanism for OCP light perception, in which the photochemical property of a conjugated carbonyl group is exploited.
EDUCATION:
• 1991-1995 Research Associate, Department of Biochemistry and Molecular Biology, The University of Chicago
• 1990-1991 Postdoctoral Research Associate, Department of Molecular Biology, The Scripps Research Institute
• 1987-1990 Department of Protein Crystallography, Institute of Biophysics, Beijing, China
• 1987-1988 Graduate School of Academia Sinica, Beijing, China
• 1983-1987 Department of Bioengineering, Huazhong University of Science and Technology, Wuhan, China
EXPERIENCE:
• 2014-present Research Associate Professor, Department of Chemistry, University of Illinois at Chicago
• 2013-present CEO, Renz Research, Inc.
• 2006-2013 Research Beamline Scientist and Software Specialist, Center for Advanced Radiation Sources, The University of Chicago at the Advance Photon Source, Argonne National Laboratory
• 2001-2006 Founder and CEO, Renz Research, Inc.
• 1995-2001 Beamline Scientist, Center for Advanced Radiation Sources, The University of Chicago at Advance Photon Source, Argonne National Laboratory
• 1995-2001 Instructor, Department of Biochemistry and Molecular Biology, The University of Chicago
RESEARCH INTERESTS
• Development of data processing algorithms for Laue diffraction and their software implementations
• Extraction of structural dynamics from diffraction data of heterogeneous conformations
• Structural meta-analysis
• Crystallization devices for large-scale in situ serial crystallography