Fig. 3: TCR–CD3–lipid interactions.
From: The resting and ligand-bound states of the membrane-embedded human T-cell receptor–CD3 complex
a Cholesterol densities in ND-I, ND-II, and GDN. Transparent green surface is the locally refined, B-factor-sharpened map, cropped to a zone of 2.2 Å around the cholesterols (black). b Comparison of GDN and ND-I cholesterol-binding sites. Insets show zoomed-in views with (left) and without (right) modeled protein highlighting the deflection of the branched aliphatic tails. c Model sections parallel to the membrane through the cholesterol-binding groove at the levels of CholA and CholB, as indicated. Locally refined, B-factor-sharpened maps are shown as black mesh, and cholesterols as green sticks. Red dashed circle highlights structured lipid density in the nanodisc adjacent to the opened cholesterol-binding groove. Insets show the cholesterol-binding groove from the same angle as the main panels, but with both cholesterols included in the slice, highlighting intercalation of the deflected CholB aliphatic chain between TM helices in nanodiscs (black dashed oval). d–g Additional densities attributable to lipids in the ND-II map. Proteins are shown as model surfaces, and cholesterol as sticks. Yellow surface is unmodeled density from the ND-II B-factor-sharpened map after local refinement (d) or non-uniform refinement (e–g). Color legend applies to (d–g).
