Time-resolved crystallography captures light-driven DNA repair
Nina Eleni Christou, Virginia Apostolopoulou, Diogo V. M. Melo, M. Ruppert, Alisia Fadini, Alessandra Henkel, Janina Sprenger, D. Oberthüer, Sebastian Günther, Anastasios Pateras, Aida Rahmani Mashhour, Oleksandr Yefanov, M. Galchenkova, P. Reinke, Viviane Kremling, Emilie Scheer, E. Lange, Philipp Middendorf, Robin Schubert, Elke De Zitter, Koya Lumbao-Conradson, Jonathan Herrmann, Simin Rahighi, Ajda Kunavar, Emma V. Beale, John H. Beale, Claudio Cirelli, Philip J. M. Johnson, Florian Dworkowski, D. Ozerov, Quentin Bertrand, Maximilian Wranik, Camila Bacellar, S. Bajt, Soichi Wakatsuki, Jonas A. Sellberg, Nils Huse, Vito Türk, Henry N. Chapman, Thomas J. Lane
Abstract
Photolyase is an enzyme that uses light to catalyze DNA repair. To capture the reaction intermediates involved in the enzyme's catalytic cycle, we conducted a time-resolved crystallography experiment. We found that photolyase traps the excited state of the active cofactor, flavin adenine dinucleotide (FAD), in a highly bent geometry. This excited state performs electron transfer to damaged DNA, inducing repair. We show that the repair reaction, which involves the lysis of two covalent bonds, occurs through a single-bond intermediate. The transformation of the substrate into product crowds the active site and disrupts hydrogen bonds with the enzyme, resulting in stepwise product release, with the 3' thymine ejected first, followed by the 5' base.