Crystallization and preliminary X-ray analysis of strictosidine synthase and its complex with the substrate tryptamine

Strictosidine synthase (STR1) is a central enzyme that participates in the biosynthesis of almost all plant monoterpenoid indole alkaloids. After heterologous expression in Escherichia coli, crystals of STR1 and its substrate complex with tryptamine were obtained by the hanging-drop technique at 302-304 K with potassium sodium tartrate tetrahydrate as precipitant. All crystals belong to space group R3. The native STR1 crystals diffract to 2.95 Å and have unit-cell parameters a = b = 150.3, c = 122.4 Å. The tryptamine complex crystals diffract to 2.38 Å, with unit-cell parameters a = b = 147.3, c = 122.3 Å.