{Reference Type}: Journal Article
{Title}: Real-time observation of a metal complex-driven reaction intermediate using a porous protein crystal and serial femtosecond crystallography.
{Author}: Maity B;Shoji M;Luo F;Nakane T;Abe S;Owada S;Kang J;Tono K;Tanaka R;Pham TT;Kojima M;Hishikawa Y;Tanaka J;Tian J;Nagama M;Suzuki T;Noya H;Nakasuji Y;Asanuma A;Yao X;Iwata S;Shigeta Y;Nango E;Ueno T;
{Journal}: Nat Commun
{Volume}: 15
{Issue}: 1
{Year}: 2024 Jun 29
{Factor}: 17.694
{DOI}: 10.1038/s41467-024-49814-9
{Abstract}: Determining short-lived intermediate structures in chemical reactions is challenging. Although ultrafast spectroscopic methods can detect the formation of transient intermediates, real-space structures cannot be determined directly from such studies. Time-resolved serial femtosecond crystallography (TR-SFX) has recently proven to be a powerful method for capturing molecular changes in proteins on femtosecond timescales. However, the methodology has been mostly applied to natural proteins/enzymes and limited to reactions promoted by synthetic molecules due to structure determination challenges. This work demonstrates the applicability of TR-SFX for investigations of chemical reaction mechanisms of synthetic metal complexes. We fix a light-induced CO-releasing Mn(CO)3 reaction center in porous hen egg white lysozyme (HEWL) microcrystals. By controlling light exposure and time, we capture the real-time formation of Mn-carbonyl intermediates during the CO release reaction. The asymmetric protein environment is found to influence the order of CO release. The experimentally-observed reaction path agrees with quantum mechanical calculations. Therefore, our demonstration offers a new approach to visualize atomic-level reactions of small molecules using TR-SFX with real-space structure determination. This advance holds the potential to facilitate design of artificial metalloenzymes with precise mechanisms, empowering design, control and development of innovative reactions.