TABLE 2.
Summary of mutants of LdNT1.1 that exhibit strong phenotypes
Crippled refers to a >95% loss of adenosine uptake activity upon mutation. PPM refers to the pellicular plasma membrane that surrounds the cell body. FPM refers to the flagellar pocket membrane at the base of the flagellum. The references refer to previously published data on mutants not examined in this study. Mutations D389N and R393L were studied in the guanosine/inosine/xanthosine transporter LdNT2 and correspond to conserved residues Asp374 and Arg378 in LdNT1.1.
| Residue | TM domain | Mutation(s) | Results | Targeting |
|---|---|---|---|---|
| Met40 | 1 | M40D | Crippled | PPM and FPM |
| Phe48 | 1 | F48A | Crippled | PPM and FPM |
| F48W | Crippled | |||
| Trp75 | 2 | W75A | Crippled | PPM and FPM |
| Glu94 | 2 | E94Q and E94D | Crippled (9) | PPM and FPM |
| Lys153 | 4 | K153A | Crippled (9) | Partially impaired |
| K153R | Change of substrate specificity (9) | PPM and FPM | ||
| Glu157 | 4/edge | E157D | Change of substrate specificity | PPM and FPM |
| E157Q | Crippled | PPM and FPM | ||
| Gly183 | 5 | G183D | Crippled (22) | PPM and FPM |
| G183A | Change of substrate specificity (22) | |||
| Cys337 | 7 | C337Y | Crippled (22) | PPM and FPM |
| Phe341 | 7 | F341A | Change of substrate specificity | PPM and FPM |
| Asp374 | 8 | D389N | Crippled (LdNT2 (12) | PPM |
| Arg378 | 8 | R393L | Crippled (LdNT2 (12) | Impaired |
| Arg404 | 9 | R404A | Crippled (9) | Impaired |
| Gly440 | 10 | G440F | Crippled | PPM and FPM |
| Ser469 | 11 | S469F | Crippled | PPM and FPM |
| Ser478 | 11 | S478F | Crippled | PPM and FPM |