Computing Alchemical Free Energy Differences with Hamiltonian Replica Exchange Molecular Dynamics (H-REMD) Simulations

被引:71
|
作者
Meng, Yilin [4 ]
Dashti, Danial Sabri [2 ,3 ]
Roitberg, Adrian E. [1 ,2 ]
机构
[1] Univ Florida, Dept Chem, Gainesville, FL 32611 USA
[2] Univ Florida, Quantum Theory Project, Gainesville, FL 32611 USA
[3] Univ Florida, Dept Phys, Gainesville, FL 32611 USA
[4] Univ Chicago, Dept Biochem & Mol Biol, Chicago, IL 60637 USA
基金
美国国家科学基金会;
关键词
BINDING FREE-ENERGY; ESCHERICHIA-COLI THIOREDOXIN; PERTURBATION CALCULATIONS; SYSTEMS; BIOMOLECULES; EFFICIENCY; EXPLICIT; COMPLEX;
D O I
10.1021/ct200153u
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Alchemical free energy calculations play a very important role in the field of molecular modeling. Efforts have been made to improve the accuracy and precision of those calculations. One of the efforts is to employ a Hamiltonian replica exchange molecular dynamics (H-REMD) method to enhance conformational sampling. In this paper, we demonstrated that the H-REMD method not only improves convergence in alchemical free energy calculations but also can be used to compute free energy differences directly via the Free Energy Perturbation (FEP) algorithm. We show a direct mapping between the H-REMD and the usual FEP equations, which are then used directly to compute free energies. The H-REMD alchemical free energy calculation (replica exchange free energy perturbation, REFEP) was tested on predicting the plc value of the buried Asp26 in thioredoxin. We compare the results of REFEP with TI and regular FEP simulations. REFEP calculations converged faster than those from TI and regular FEP simulations. The final predicted pK(a) value from the H-REMD simulation was also very accurate, only 0.4 pK(a) units above the experimental value. Utilizing the REFEP algorithm significantly improves conformational sampling, and this in turn improves the convergence of alchemical free energy simulations.
引用
收藏
页码:2721 / 2727
页数:7
相关论文
共 50 条