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Racigh V, Ormazábal A, Palma J, Pierdominici-Sottile G. Positively Charged Residues in the Head Domain of P2X4 Receptors Assist the Binding of ATP. J Chem Inf Model 2020; 60:923-932. [PMID: 31747275 DOI: 10.1021/acs.jcim.9b00856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
P2X receptors are a family of trimeric cationic channels located in the membrane of mammalian cells. They open in response to the binding of ATP. The differences between the closed and open structures have been described in detail for some members of the family. However, the order in which the conformational changes take place as ATP enters the binding cleft, and the residues involved in the intermediate stages, are still unknown. Here, we present the results of umbrella sampling simulations aimed to elucidate the sequence of conformational changes that occur during the reversible binding of ATP to the P2X4 receptor. The simulations also provided information about the interactions that develop in the course of the process. In particular, they revealed the existence of a metastable state which assists the binding. This state is stabilized by positively charged residues located in the head domain of the receptor. Based on these findings, we propose a novel mechanism for the capture of ATP by P2X4 receptors.
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Affiliation(s)
- Vanesa Racigh
- Departamento de Ciencia y Tecnología , Universidad Nacional de Quilmes , Sáenz Peña 352 , B1876BXD Bernal, Buenos Aires , Argentina.,Consejo Nacional de Investigaciones Cientficas y Técnicas , CONICET , B1876BXD Bernal, Buenos Aires , Argentina
| | - Agustín Ormazábal
- Departamento de Ciencia y Tecnología , Universidad Nacional de Quilmes , Sáenz Peña 352 , B1876BXD Bernal, Buenos Aires , Argentina.,Consejo Nacional de Investigaciones Cientficas y Técnicas , CONICET , B1876BXD Bernal, Buenos Aires , Argentina
| | - Juliana Palma
- Departamento de Ciencia y Tecnología , Universidad Nacional de Quilmes , Sáenz Peña 352 , B1876BXD Bernal, Buenos Aires , Argentina.,Consejo Nacional de Investigaciones Cientficas y Técnicas , CONICET , B1876BXD Bernal, Buenos Aires , Argentina
| | - Gustavo Pierdominici-Sottile
- Departamento de Ciencia y Tecnología , Universidad Nacional de Quilmes , Sáenz Peña 352 , B1876BXD Bernal, Buenos Aires , Argentina.,Consejo Nacional de Investigaciones Cientficas y Técnicas , CONICET , B1876BXD Bernal, Buenos Aires , Argentina
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