LAUSR

Significance Clarifying the recognition pathways of agonist and G protein to G protein–coupled receptor (GPCR) is essential to understand the signal transduction mechanism of GPCR. However, it is still challenging to simulate the full activation process of GPCR on a reasonable simulation timescale with conventional molecular dynamics (MD) methods. Here, we developed an MD simulation approach named supervised Gaussian accelerated MD (Su-GaMD) and revealed the full activation mechanism of adenosine (Ado) A1 receptor (A1R) (including adenosine Ado−A1R recognition, preactivation of A1R, and A1R−G protein recognition) in hundreds of nanoseconds simulations. The whole activation process and the metastable intermediate states revealed in this study could provide complementary structural characterizations to expand our perspectives on A1R drug discovery.