Fig. 4: Structural rearrangements upon GABA binding and gating in a heteromeric GABAAR.
From: Disentangling the mechanistic role of loop-C capping in Cys-loop receptor activation
a–d Different views of globally superposed atomic models of closed (unliganded orthosteric sites; PDB ID: 6HUG10) and desensitized (orthosteric sites bound to GABA; PDB ID: 6HUO10) (α1)2(β3)2γ2L GABAAR. One subunit is highlighted, and its loop C is colored blue (unliganded) or red (GABA-bound); bound GABA is colored purple; and all other atoms are colored yellow (unliganded) or dark cyan (GABA-bound). In (a–c), the highlighted subunit is one of the β3 subunits. In (d), the highlighted subunit is one of the α1 subunits. Different structural elements at the ECD–TMD interface are indicated. The structural rearrangements of loop C and elements of the ECD–TMD interface illustrated here on an atomic model of a heteromeric GABAAR are representative of structural rearrangements occurring upon the binding of small-molecule agonists and gating in other members of the superfamily. The molecular images were made with VMD57 using cartoon representation for the protein and surface representation for the agonist.
