Figure 38.

(a) Stereoview of an electron density map calculated with Fourier coefficients 2|F_o| – |F_c| and phases calculated from the final model showing (−)-limonene synthase complexed with substrate analogue 2-fluorolinalyl diphosphate generated enzymatically from 2-fluorogeranyl diphosphate. The analogue binds in an extended conformation that is not productive with regard to the cyclization reaction. (b) Stereoview of an electron density map calculated with Fourier coefficients 2|F_o| – |F_c| and phases calculated from the final model showing (−)-limonene synthase complexed with substrate analogue 2-fluorolinalyl diphosphate prepared by direct cocrystallization. The analogue binds in a helical conformation that is productive for the cyclization reaction. Reprinted from ref (190). Copyright 2007 National Academy of Sciences.