Crystallization and preliminary analysis of neurolysin

Neuropeptidases inactivate or modify the activity of peptide neurotransmitters and neurohormones. The neuropeptidase neurolysin acts only on short peptides and accepts a variety of cleavage-site sequences. Structures of the enzyme and enzyme–substrate complexes will help to determine the mechanisms of substrate selectivity used by this enzyme. Crystals of recombinant neurolysin have been grown in the orthorhombic space group P2₁2₁2, with unit-cell parameters a = 157.8, b = 88.0, c = 58.4 Å. Data have been collected to 2.3 Å at 110 K with observed diffraction to 1.8 Å. Circular dichroism measurements suggest that the enzyme is primarily α-helical, with little β-strand secondary structure. Sequence-based secondary-structure prediction supports this ­conclusion.