2.1.1.300 Structural and functional studies of pavine N-methyltransferase from Thalictrum flavum reveal novel insights into substrate recognition and catalytic mechanism Thalictrum flavum subsp. glaucum 2.1.1.300 Purification, crystallization and X-ray diffraction analysis of pavine N-methyltransferase from Thalictrum flavum Thalictrum flavum