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 D(2)O. Although the crystal sizes were the same, crystals grown using solutions made up in H(2)O in the initial stages of macroseeding and solutions with D(2)O in later stages did not diffract neutrons well. However, when the protein was initially exchanged with buffered D(2)O and then crystallized and also macroseeded using solutions made up in D(2)O 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 A.