Additionally, the site equivalent to the most widespread cystic fibrosis linked mutant, (CFTR delF506) Ycf1 F713, is located in NBD1 directly adjacent to the phosphorylation sites of the R-domain and is coordinated by cation-pi interactions with two conserved arginine side chains, R765 and R1150 (Supplementary Fig. 7h). Here, CFTR is linked to cystic fibrosis.