Figure 1. Introduction of photocrosslinking UAAs into hSERT.

(a) X-ray crystal structure of dDAT with nortriptyline bound (PDB ID 4M48). The location of the S1- and S2-binding sites are illustrated with orange and purple dashed lines, respectively. TM10 and TM11 have been removed for clarity. (b) Chemical structures of azF and BzF. (c) Specificity of azF incorporation. The [³H]5-HT uptake activity of five azF mutants (Y95azF, W103azF, Y175azF, F341azF and K490azF) where one of the transfection components (suppressor tRNA, aaRS or azF) was omitted. Data are represented as mean±s.e.m. from three independent experiments each performed in triplicate. (d) Two-dimensional schematic representation of hSERT showing the location of the 75 positions that were mutated to azF or BzF. Blue circles indicate positions where azF introduction resulted in a functionally active transporter (defined as >5% functional activity relative to WT hSERT activity), while white circles indicate positions where introduction of azF abolished activity (see Supplementary Table 1 and Supplementary Fig. 1 for transport activity of BzF mutants). Circles highlighted with a red line designate the positions examined in c. TM, transmembrane.