title: Q|R: quantum-based refinement.
abstract: Quantum-based refinement utilizes chemical restraints derived from quantum-chemical methods instead of the standard parameterized library-based restraints used in refinement packages. The motivation is twofold: firstly, the restraints have the potential to be more accurate, and secondly, the restraints can be more easily applied to new molecules such as drugs or novel cofactors. Here, a new project called Q|R aimed at developing quantum-based refinement of biomacromolecules is under active development by researchers at Shanghai University together with PHENIX developers. The central focus of this long-term project is to develop software that is built on top of open-source components. A development version of Q|R was used to compare quantum-based refinements with standard refinement using a small model system.
authors.affiliation: Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University, Shanghai, 200444, People's Republic of China.
authors.forename: Min
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University, Shanghai, 200444, People's Republic of China.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Reimers
authors.affiliation: Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University, Shanghai, 200444, People's Republic of China.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Waller
authors.affiliation: Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University, Shanghai, 200444, People's Republic of China.
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Afonine
keywords: Q|R; X-ray diffraction; cctbx; cryo-EM; neutron diffraction; quantum refinement; structural biology