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Figure 3
The ionic networks in the mutation-induced inactive M4 structure. (a) Alignment of the structures of M2–AF-DX 384 (PDB entry 5zkb; grey cartoon) and mutation-induced inactive M4 (teal blue cartoon). (b) In the mutation-induced inactive M4 structure (top), S1193.39, D782.50 and R4497.49 form an ionic network, while in the M2 structure (bottom) D692.50, S4337.46 and R1103.39 form a salt-bridge interaction. (c) The distance between CG of D782.50 and CZ of R4497.49 during MD simulation of Ach-bound or tiotropium-bound M41 (top) and M46 (bottom). The detailed information is from the computational analysis of mutation-induced inactive M4. (d) Comparison of the sodium-binding site in the ZM241385–A2A structure (PDB entry 4eiy; lemon) and the ionic network around R4497.49 in mutation-induced inactive M4.

IUCrJ
Volume 7| Part 2| March 2020| Pages 294-305
ISSN: 2052-2525
https://doi.org/10.1107/S2052252520000597