Extended Data Fig. 3: Comparison of LetA with structural homologs, related to Fig. 2.
From: LetA defines a structurally distinct transporter family
a, Left, surface representation of LetAB, highlighting LetA (gray) and MCE Ring 1 (colored by chain). Middle, cartoon representation of LetA (gray, with the periplasmic sheet in yellow and orange) and MCE Ring 1 of LetB (colored by chain). Inset (right) highlights the periplasmic sheet of LetA and pore-lining loops of LetB. Residues involved in the putative lipid transport pathway are shown as sticks and labeled. b, ICP-MS results showing elemental scanning analysis for 10 transition metals. Average parts per billion (ppb) values of two independent experiments are shown for LetA and buffer control samples. To reflect the semi-quantitative nature of this data, values are reported to just one significant figure. c, d, Cartoon representations with helices shown as cylinders (c) and corresponding topology diagrams (d) of tetraspanin42 (CD81, PDB 5TCX), and vitamin K epoxide reductase-like41 (VKORL, PDB 6WV8). The secondary structural elements of LetA TMDN conserved with structurally related proteins are colored as in Fig. 2c. e, Surface representations of tetraspanin, VKORL and LetA TMDN, colored by electrostatic potential. Cholesterol and vitamin K1 binding pockets of tetraspanin and VKORL, respectively, are shown, and the corresponding region on LetA TMDC is indicated with a dotted circle (periplasmic pocket). f, AlphaFold models of LetA-like proteins from the species indicated. Uniprot IDs are provided in parentheses. Models are colored by the predicted local distance difference test (pLDDT) scores.
