Purification, crystallization and X-ray diffraction analysis of pavine N-methyltransferase from Thalictrum flavum

A cDNA from the plant Thalictrum flavum encoding pavine N-methyltrans­ferase, an enzyme belonging to a novel class of S-adenosylmethionine-dependent N-methyltransferases specific for benzylisoquinoline alkaloids, has been heterologously expressed in Escherichia coli. The enzyme was purified using affinity and gel-filtration chromatography and was crystallized in space group P2₁. The structure was solved at 2.0 Å resolution using a xenon derivative and the single isomorphous replacement with anomalous scattering method.