V1/2 of G-V relation for a variety of mutations with or without MTS modification
| No. | Charge at 172 | Charge at 399 | Interaction | V1/2 |
| mV | ||||
| 1 | 0 (Cys) | 0 (Cys) | 0 | 197 ± 5 |
| 2 | − (Cys/ES) | − (Cys/ES) | Rep | 250 ± 9 |
| 3 | + (Cys/ET) | + (Cys/ET) | Rep | 271 ± 9 |
| 4 | 0 (Cys) | − (Glu) | 0 | 193 ± 2 |
| 5 | − (Cys/ES) | − (Glu) | Rep | 236 ± 3 |
| 6 | + (Cys/ET) | − (Glu) | Attr | 174 ± 4 |
| 7 | 0 (Asn) | 0 (Cys) | 0 | 167 ± 4 |
| 8 | 0 (Asn) | − (Cys/ES) | 0 | 190 ± 2 |
| 9 | 0 (Asn) | + (Cys/ET) | 0 | 201 ± 2 |
| 10 | − (Asp) | 0 (Cys) | 0 | 203 ± 2 |
| 11 | − (Asp) | − (Cys/ES) | Rep | 237 ± 3 |
| 12 | − (Asp) | + (Cys/ET) | Attr | 177 ± 4 |
| 13 | + (Arg) | 0 (Cys) | 0 | 148 ± 3 |
| 14 | + (Arg) | − (Cys/ES) | Attr | 165 ± 7 |
| 15 | + (Arg) | + (Cys/ET) | Rep | 203 ± 2 |
| 16 | 0 (Asn) | − (Glu) | 0 | 198 ± 2 |
| 17 | + (Arg) | − (Glu) | Attr | 139 ± 1 |
| 18 | + (Arg) | + (Arg) | Rep | 172 ± 4 |
| 19 | − (Asp) | − (Glu) | Rep | 211 ± 3 |
| 20 | − (Asp) | 0 (Asn) | 0 | 200 ± 4 |
| 21 | − (Asp) | + (Arg) | Attr | 153 ± 3 |
| 22 | 0 (Asn) | 0 (Asn) | 0 | 170 ± 4 |
| 23 | 0 (Asn) | + (Arg) | 0 | 172 ± 3 |
| 24 | 0 (Gln) | − (Glu) | 0 | 181 ± 2 |
| 25 | 0 (Gln) | 0 (Asn) | 0 | 186 ± 3 |
| 26 | 0 (Gln) | + (Arg) | 0 | 184 ± 3 |
| P | 0.049a | 0.364 | 0.0006a |
| No. | Charge at 172 | Charge at 399 | Interaction | V1/2 |
| mV | ||||
| 1 | 0 (Cys) | 0 (Cys) | 0 | 197 ± 5 |
| 2 | − (Cys/ES) | − (Cys/ES) | Rep | 250 ± 9 |
| 3 | + (Cys/ET) | + (Cys/ET) | Rep | 271 ± 9 |
| 4 | 0 (Cys) | − (Glu) | 0 | 193 ± 2 |
| 5 | − (Cys/ES) | − (Glu) | Rep | 236 ± 3 |
| 6 | + (Cys/ET) | − (Glu) | Attr | 174 ± 4 |
| 7 | 0 (Asn) | 0 (Cys) | 0 | 167 ± 4 |
| 8 | 0 (Asn) | − (Cys/ES) | 0 | 190 ± 2 |
| 9 | 0 (Asn) | + (Cys/ET) | 0 | 201 ± 2 |
| 10 | − (Asp) | 0 (Cys) | 0 | 203 ± 2 |
| 11 | − (Asp) | − (Cys/ES) | Rep | 237 ± 3 |
| 12 | − (Asp) | + (Cys/ET) | Attr | 177 ± 4 |
| 13 | + (Arg) | 0 (Cys) | 0 | 148 ± 3 |
| 14 | + (Arg) | − (Cys/ES) | Attr | 165 ± 7 |
| 15 | + (Arg) | + (Cys/ET) | Rep | 203 ± 2 |
| 16 | 0 (Asn) | − (Glu) | 0 | 198 ± 2 |
| 17 | + (Arg) | − (Glu) | Attr | 139 ± 1 |
| 18 | + (Arg) | + (Arg) | Rep | 172 ± 4 |
| 19 | − (Asp) | − (Glu) | Rep | 211 ± 3 |
| 20 | − (Asp) | 0 (Asn) | 0 | 200 ± 4 |
| 21 | − (Asp) | + (Arg) | Attr | 153 ± 3 |
| 22 | 0 (Asn) | 0 (Asn) | 0 | 170 ± 4 |
| 23 | 0 (Asn) | + (Arg) | 0 | 172 ± 3 |
| 24 | 0 (Gln) | − (Glu) | 0 | 181 ± 2 |
| 25 | 0 (Gln) | 0 (Asn) | 0 | 186 ± 3 |
| 26 | 0 (Gln) | + (Arg) | 0 | 184 ± 3 |
| P | 0.049a | 0.364 | 0.0006a |
The charge type is listed for each mutation using symbols (+, positive; −, negative; 0, neutral), along with the amino acid and MTS reagent. As a result, the electrostatic interaction between 172 and 399 can be repulsion (Rep, between like charges), attraction (Attr, between opposite charges), or 0 (not both are charged). The p-values are calculated using ANOVA test (see Materials and methods). Mutations 1–18 are on the background of C430A.
A p-value of <0.05 indicates that a significant difference among the V1/2 values was detected with different charge or interaction type.