Neighbor network around position 457 proposed by comparative modeling. All residues in this structural schematic are numbered according to fCNGA2 sequence position. Glutamate is shown in position 457, with black dashed lines indicating its interactions with first neighbors (see Discussion). Parentheses indicate residues that are not identified as first neighbors when valine occupies position 457. Gray dashed lines indicate interactions between first neighbors (black type) and second neighbors (gray type). E458 is capable of forming hydrogen bonds or polar contact with both E457 and K462 (thick dashed lines); other neighbor interactions shown are not polar.