research papers
The laccase from Steccherinum murashkinskyi is a member of the large family of multicopper oxidases that catalyze the oxidation of a wide range of organic and inorganic substrates, accompanied by the reduction of dioxygen to water. The reducing properties of X-ray radiation and the high quality of the laccase crystals allow the study of the catalytic reduction of dioxygen to water directly in a crystal. A series of diffraction data sets with increasing absorbed radiation dose were collected from a single crystal of Steccherinum murashkinskyi laccase at 1.35 Å resolution. Changes in the active-site structure associated with the reduction of molecular oxygen to water on increasing the absorbed dose of ionizing radiation were detected. The structures in the series are mixtures of different states of the enzyme–substrate complex. Nevertheless, it was possible to interpret these structures as complexes of various oxygen ligands with copper ions in different oxidation states. The results allowed the mechanism of oxygen reduction catalyzed by laccases to be refined.
Keywords: laccase; serial X-ray data; enzymatic oxygen reduction; photo-electron reduction; reaction mechanisms.
Supporting information
Portable Document Format (PDF) file https://doi.org/10.1107/S2059798317003667/dw5176sup1.pdf |
PDB references: Steccherinum murashkinskyi laccase, 3 min exposure, 5mej; 33 min exposure, 5mew; 63 min exposure, 5mhu; 93 min exposure, 5mhv; 123 min exposure, 5mhw; 153 min exposure, 5mhx; 183 min exposure, 5mhy; 213 min exposure, 5mhz; 243 min exposure, 5mi1; 273 min exposure, 5mi2; 303 min exposure, 5mia; 333 min exposure, 5mib; 363 min exposure, 5mic; 393 min exposure, 5mid; 423 min exposure, 5mie; 453 min exposure, recooled crystal, 5mig