### Abstract

A novel procedure has been applied to compute experimentally unobserved intrinsic kinetic isotope effects upon the rearrangement of chorismate to prephenate catalyzed by B. subtilis chorismate mutase. In this modified QM/MM approach, the "low-level" QM description of the quantum region is corrected during the optimization procedure by means of a "high-level" calculation in vacuo, keeping the QM-MM interaction contribution at a quantum "low-level". This allows computation of energies, gradients, and Hessians including the polarization of the QM subsystem and its interaction with the MM environment, both terms calculated using the low-level method at a reasonable computational cost. New information on an important enzymatic transformation is provided with greater reliability than has previously been possible. The predicted kinetic isotope effects on V-max/K-m are 1.33 and 0.86 (at 30 degreesC for 5-H-3 and 9-H-3(2) substitutions, respectively, and 1.011 and 1.055 at 22 degreesC) for 1-C-13 and 7-O-18 substitutions, respectively.

Original language | English |
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Pages (from-to) | 3707-3710 |

Number of pages | 4 |

Journal | Journal of Physical Chemistry B |

Volume | 109 |

Issue number | 9 |

DOIs | |

Publication status | Published - 2005 |

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## Cite this

Marti, S., Moliner, V., Tunon, M., & Williams, I. H. (2005). Computing kinetic isotope effects for chorismate mutase with high accuracy. A new DFT/MM strategy.

*Journal of Physical Chemistry B*,*109*(9), 3707-3710. https://doi.org/10.1021/jp044387u