Fig. 3: Cryo-EM structure of retinal-free proteoopsin (PO). | Nature Communications

Fig. 3: Cryo-EM structure of retinal-free proteoopsin (PO).

From: Structural insights into the mechanism and dynamics of proteorhodopsin biogenesis and retinal scavenging

Fig. 3: Cryo-EM structure of retinal-free proteoopsin (PO).The alternative text for this image may have been generated using AI.

A Top and side views of the PO pentamer cryo-EM structure. Individual protomers are labelled in the top view (seen from the extracellular side), lipid bilayer boundaries (based on the PPM server64) and symmetry axis are indicated in the side view. Ligand densities are highlighted in orange. B The decanoate molecule (orange) in the chromophore binding pocket is shown with interacting residues (green). C Close-up view of the chromophore binding pocket with decanoate cryo-EM density (blue mesh). The carboxylate of decanoate forms a salt bridge with K232 (interaction distances indicated in Å) and the acyl chain is surrounded by hydrophobic residues. D Structural comparison of decanoate-bound PO (green) and retinal-bound GPR (magenta, PDB ID: 7B03) viewed from the extracellular space. Transmembrane α-helices are labelled (A–G) in (C) and (D).

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