To obtain low pH conditions in the LPMO crystal, a large crystal was harvested and mounted in a quartz capillary to which a deuterated low pH buffer was added to facilitate vapor exchange in three stages. The first vapor exchange was performed in 22% PEG 3350 and 100 mM sodium acetate pD 5.6 (pH 5.2) for three days, followed by 22% PEG 3350 and 100 mM sodium acetate pD 5.2 (pH 4.8) for six days and 22% PEG 3350 and 100 mM sodium acetate pD 4.8 (pH 4.4) for 16 days. 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. Following this, an X-ray dataset was collected on the same crystal at 298 K using a copper rotating-anode home source.