Molecular insights into the dynamics of pharmacogenetically important N-terminal variants of the human β2-adrenergic receptor

PLoS Comput Biol. 2014 Dec 11;10(12):e1004006. doi: 10.1371/journal.pcbi.1004006. eCollection 2014 Dec.

Abstract

The human β2-adrenergic receptor (β2AR), a member of the G-protein coupled receptor (GPCR) family, is expressed in bronchial smooth muscle cells. Upon activation by agonists, β2AR causes bronchodilation and relief in asthma patients. The N-terminal polymorphism of β2AR at the 16th position, Arg16Gly, has warranted a lot of attention since it is linked to variations in response to albuterol (agonist) treatment. Although the β2AR is one of the well-studied GPCRs, the N-terminus which harbors this mutation, is absent in all available experimental structures. The goal of this work was to study the molecular level differences between the N-terminal variants using structural modeling and atomistic molecular dynamics simulations. Our simulations reveal that the N-terminal region of the Arg variant shows greater dynamics than the Gly variant, leading to differential placement. Further, the position and dynamics of the N-terminal region, further, affects the ligand binding-site accessibility. Interestingly, long-range effects are also seen at the ligand binding site, which is marginally larger in the Gly as compared to the Arg variant resulting in the preferential docking of albuterol to the Gly variant. This study thus reveals key differences between the variants providing a molecular framework towards understanding the variable drug response in asthma patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Albuterol / chemistry
  • Albuterol / metabolism
  • Asthma / genetics
  • Binding Sites / genetics*
  • Humans
  • Molecular Dynamics Simulation
  • Pharmacogenetics
  • Polymorphism, Genetic / genetics*
  • Receptors, Adrenergic, beta-2 / chemistry*
  • Receptors, Adrenergic, beta-2 / genetics*
  • Receptors, Adrenergic, beta-2 / metabolism

Substances

  • Receptors, Adrenergic, beta-2
  • Albuterol

Grants and funding

DS gratefully acknowledges the support of the Ramalingaswami Fellowship from the Department of Biotechnology, Govt. of India. MJ thanks the Ministry of Communications and Information Technology, Government of India and Bioinformatics Center, University of Pune for financial support. DS acknowledges the CSIR Fourth Paradigm Institute (Bangalore) and the CSIR Multi-Scale Simulation and Modeling project - MSM (CSC0129) for computational time. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.