Structural and Computational Insight into the Catalytic Mechanism of Limonene Epoxide Hydrolase Mutants in Stereoselective Transformations, JACS (2017), DOI: 10.1021/jacs.7b10278

Zhoutong Sun, Lian Wu, Marco Bocola, H.C. Stephen Chan, Richard Lonsdale, Xu-Dong Kong, Shuguang Yuan*, Jiahai Zhou*, and Manfred T. Reetz*

Stereo selectivity is an important topic inenzyme catalysis research as well as in computational structural biology.Recently, we have successfully combined quantum mechanics (QM) with moleculardynamics (MD) simulations to depict the stereo selectivity of limonene epoxidehydrolase (LEH).

When substrates approach LEH, they caninduce large fluctuation in H4, C loop and loop A, which opens space for theentrance of the respective compounds. Subsequently, an activated highlyconserved water molecule, hydrogen-bonded with Y53, N55 and D132, can undergonucleophilic attack in two different ways: reaction either at C1 or at C2 ofthe epoxide moiety . If the distance between water and C1 (d1) is shorter than thatof C2 (d2), LEH favors the formation of the (R,R)-products. This stereoselectivity is supported by the QM-computed lower activation energy.