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 P 2 1 . The structure was solved at 2.0 Å resolution using a xenon derivative and the single isomorphous replacement with anomalous scattering method.