AA shows long-lived interactions with protein sites in atomistic simulations. (A) Time-resolved occupancy of AA at three sites in one of three 500 ns repeats of a backmapped atomistic setup. Dark blue indicates presence of AA, i.e., when the carboxylic acid carbon of AA is within 4.5 Å of the R65_hASIC3 sidechain. (B) Distances between the carboxylic acid carbon of AA and ζ-carbon of R65_hASIC3 over time of three initially bound AA molecules at three chains. (C) An example of a putative salt bridge interaction between the headgroup of AA and guanidinium groups of R65_hASIC3 and R68 _hASIC3, with a potential van der Waals interaction of the AA tail with Y58_hASIC3. The protein structure is shown in cyan cartoon, while residues of interest are shown as sticks with carbon atoms colored in cyan. AA is shown as stick representation with carbon atoms colored in orange.