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Liu X, Xue Q, Zhang H, Fu J, Zhang A. Structural basis for molecular recognition of G protein-coupled estrogen receptor by selected bisphenols. Sci Total Environ 2021; 793:148558. [PMID: 34328988 DOI: 10.1016/j.scitotenv.2021.148558] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
Complicated ligand-dependent signaling pathways of bisphenol A (BPA) and its analogues involve not only intranuclear estrogen receptor but also membrane receptor G protein-coupled estrogen receptor (GPER). However, the structural basis for molecular recognition of GPER by the environmental chemicals remains unknown. To reveal the structural dependence of GPER recognition by bisphenols, a systematic molecular dynamics simulation study was performed for selected bisphenols with different electron hybrid orbitals and substituents on their C atoms connecting two phenol rings. BPA was used as a control, bisphenol C(BPC) as an example for a connecting C with sp2 hybrid orbitals to provide more ligand rigidity, bisphenol E(BPE) and bisphenol F(BPF) for decreased steric hindrance and hydrophobicity around the connecting C, and bisphenol B(BPB) and bisphenol AF(BPAF) for increased hydrophobicity and steric hindrance. All the tested bisphenols can bind with GPER at its classic orthosteric site to obtain GPER-ligand complexes, while van der Waals interactions and direct inter-molecular electrostatic energies provide the driving forces for ligand binding. Bulky substituents and structural rigidity of the connecting C dramatically impair hydrogen bonding between GPER and the bisphenols, which results in decreased contribution of both favorable intermolecular hydrogen bonds and unfavorable polar solvation effect to complex stability of BPB and BPC since decreased number of key residues is expected. Increase in substituent lipophilicity enhances the van der Waals interactions and favorable non-polar solvation effect. The six bisphenols of high structural similarity shared two key recognition residues, Leu137TM3 and Trp272TM6, the latter of which was in the highly conserved CWxP motif of TM6 and has been reported as key residue for G protein-coupled receptor activation. Based on the obtained knowledge, GPER affinity and relevant toxicity of BPA alternatives can be easily predicted, and the calculated binding free energies are consistent with the available experimental observations.
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Affiliation(s)
- Xiuchang Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, PR China
| | - Qiao Xue
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China
| | - Huazhou Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, PR China
| | - Jianjie Fu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310012, PR China
| | - Aiqian Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, PR China; School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310012, PR China.
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