3 years ago

Improvement of the self-consistent-charge density-functional-tight-binding theory by a modified Mulliken charge

Xia Wang, Jianzhuang Yao


Although extensive efforts had been carried out to improve the accuracy of the self-consistent-charge density-functional-tight-binding (SCC-DFTB), the application of SCC-DFTB on biological systems (e.g., enzymes) is still limited. Our benchmark calculations show that the original SCC-DFTB/MM is not able to properly descript the human carboxylesterase 1 (CES1) catalyzed hydrolysis of d-threo-methylphenidate (dMD). In contrast to the ab initio QM/MM results, SCC-DFTB/MM underestimates the activation free energy barrier and renders the acylation process as a single-step reaction without a tetrahedral intermediate. It seems like that SCC-DFTB/MM misestimates the developing negative QM Mulliken charge of the substrate oxygen atom in the oxyanion hole. To improve the SCC-DFTB energy and the electrostatic interaction between QM (SCC-DFTB) and MM atoms, we adopt an optimization strategy for QM Mulliken charge, in which an empirical parameter is trained to fit the SCC-DFTB Mulliken charge to high-level DFT method along the reaction coordinate. Herein, the optimized Mulliken charge-based SCC-DFTB method is denoted as SCC-DFTBMR. Finally, benchmark and free energy calculations were performed to prove the applicability of SCC-DFTBMR to CES1-catalyzed reaction.

Publisher URL: https://link.springer.com/article/10.1007/s00214-017-2156-1

DOI: 10.1007/s00214-017-2156-1

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.