A preliminary time-of-flight neutron diffraction study on amicyanin from Paracoccus denitrificans

Crystals of the blue copper protein amicyanin suitable for neutron diffraction were grown by the sitting-drop method, followed by repeated macroseeding using solutions prepared with D₂O. Although the crystal sizes were the same, crystals grown using solutions made up in H₂O in the initial stages of macroseeding and solutions with D₂O in later stages did not diffract neutrons well. However, when the protein was initially exchanged with buffered D₂O and then crystallized and also macroseeded using solutions made up in D₂O throughout, the crystals diffracted neutrons to high resolution. One of those crystals was used to collect a data set to a resolution of 1.9 Å.