Conformational changes of the hOCT1 protein induced by the M420del and/or M408V SNPs. Model was created using the Swiss model software (http://swissmodel.expasy.org/). (A) Undeleted M420 with M408. (B) M420del with M408. (C) undeleted M420 with V408. (D) M420del with V408. In each panel, the left side depicts the lateral view of the folded protein and the right shows the dorsal view of the pore (P). Differences in protein folding are observed in the cytoplasmic domain (CPD) if M420del is present; the M420del+V408 combination also alters the transmembrane domain (TMD). A clear blockage of the pore (P) is also observed in the presence of M420del, although this is less marked when V408 is present.