Fig. 1: Overall structure of the mCAT1/frRBD complex.
From: Structural insights into cationic amino acid transport and viral receptor engagement by CAT1
a Biolayer interferometry (BLI) sensorgrams showing concentration-dependent binding of frRBD (1.6~25 nM, indicated) to purify mCAT1. The y-axis represents response (nm). Global fitting yielded a dissociation constant (KD) of 5.91 ± 0.07 nM. One representative experiment of 3 is shown. b Size-exclusion chromatography (SEC) profile of the purified mCAT1/frRBD complex, monitored by UV absorbance at 280 nm (mAU). Fractions analyzed by SDS–PAGE are shown below. This purification experiment was performed once, and the result shown is representative. c Cryo-EM structure of the mCAT1/frRBD complex. Left, overall density map with fitted atomic models. Right, ribbon representation rotated 180°, highlighting the extracellular loops ECL3 and ECL4 of mCAT1 (forest green) and the bound frRBD (orange). Grey transparent density represents the overall reconstruction; segmented densities for mCAT1 and frRBD are shown in green and orange, respectively. d Topology diagram of mCAT1 showing 14 transmembrane helices and major extracellular (ECL, extracellular loop) and intracellular loops (ICL, intracellular loop). Two additional transmembrane helices (ATM1 and ATM2) are also indicated. The disulfide linkage between C226 and C309 connecting ECL3 and ECL4 is highlighted in gold.
