To reduce the copper active site, a large crystal was harvested and placed in a deuterated buffer containing 100 mM HEPES pD 6.0 (pH 5.6), 25 % PEG 3350 and 100mM ascorbic acid pD 6.0 (pH 5.6). The crystal was incubated for two hours after which it was flash-frozen in liquid nitrogen using the deuterated buffer supplemented with 25 % glycerol as cryoprotectant. Time-of-flight neutron diffraction data were collected on beamline 11B, the Macromolecular Neutron Diffractometer (MaNDi) at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. 62