| Species | Original | Mutated to | Mutation | |
| Human | Glu 549 | |||
| Rat Equivalent | Glu 584 | Arg | ||
| Mouse Equivalent | Glu 583 | |||
This mutation had little effect on the single-channel conductance. When it was combined with R436D, the double mutation produced conductance that was greater than the sum of the individual mutations. When it was combined with R440A, there was no such synergy. In a triple mutation of R432Q, R436D, and R440A, the single-channel conductance increased substantially.
See Equivalent Mutation in R432Q