Supplementary Figure 5: The substrate-binding site of PnuC.
From: Crystal structure of the vitamin B3 transporter PnuC, a full-length SWEET homolog
(a) Stereo image of 2Fo-Fc electron density map (contoured at 1.5σ) for the bound NR molecule and side chains of amino acids forming the binding site.
(b) Sliced-through surface representation of PnuC showing TM3 (green), TM 7 (red) and the NR molecule (yellow). On the periplasmic side two symmetry-related tyrosines (Tyr95 and Tyr217) are located at the same height as the 5'OH group of the ribose, but do not close the binding pocket. Instead, a cavity extends for one more turn of the TMs.
