Crystal Structure of an LSD-Bound Human Serotonin Receptor

Cell. 2017 Jan 26;168(3):377-389.e12. doi: 10.1016/j.cell.2016.12.033.

Abstract

The prototypical hallucinogen LSD acts via serotonin receptors, and here we describe the crystal structure of LSD in complex with the human serotonin receptor 5-HT2B. The complex reveals conformational rearrangements to accommodate LSD, providing a structural explanation for the conformational selectivity of LSD's key diethylamide moiety. LSD dissociates exceptionally slow from both 5-HT2BR and 5-HT2AR-a major target for its psychoactivity. Molecular dynamics (MD) simulations suggest that LSD's slow binding kinetics may be due to a "lid" formed by extracellular loop 2 (EL2) at the entrance to the binding pocket. A mutation predicted to increase the mobility of this lid greatly accelerates LSD's binding kinetics and selectively dampens LSD-mediated β-arrestin2 recruitment. This study thus reveals an unexpected binding mode of LSD; illuminates key features of its kinetics, stereochemistry, and signaling; and provides a molecular explanation for LSD's actions at human serotonin receptors. PAPERCLIP.

Keywords: GPCR; crystallography; hallucinogens; serotonin receptor; structure-function.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arrestin / chemistry
  • Crystallography, X-Ray
  • Humans
  • Kinetics
  • Lysergic Acid Diethylamide / chemistry*
  • Models, Chemical
  • Molecular Dynamics Simulation
  • Receptor, Serotonin, 5-HT2B / chemistry*

Substances

  • Arrestin
  • Receptor, Serotonin, 5-HT2B
  • Lysergic Acid Diethylamide