7sfj

ChRmine in MSP1E3D1 lipid nanodisc

spinqualitylabelsall models 7sfj, resolution 2.74Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7sfj is a 3 chain structure with sequence from Rhodomonas lens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AYA, PEE, RET Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Microbial channelrhodopsins are light-gated ion channels widely used for optogenetic manipulation of neuronal activity. ChRmine is a bacteriorhodopsin-like cation channelrhodopsin (BCCR) more closely related to ion pump rhodopsins than other channelrhodopsins. ChRmine displays unique properties favorable for optogenetics including high light sensitivity, a broad, red-shifted activation spectrum, cation selectivity, and large photocurrents, while its slow closing kinetics impedes some applications. The structural basis for ChRmine function, or that of any other BCCR, is unknown. Here, we present cryo-EM structures of ChRmine in lipid nanodiscs in apo (opsin) and retinal-bound (rhodopsin) forms. The structures reveal an unprecedented trimeric architecture with a lipid filled central pore. Large electronegative cavities on either side of the membrane facilitate high conductance and selectivity for cations over protons. The retinal binding pocket structure suggests channel properties could be tuned with mutations and we identify ChRmine variants with ten-fold decreased and two-fold increased closing rates. A T119A mutant shows favorable properties relative to wild-type and previously reported ChRmine variants for optogenetics. These results provide insight into structural features that generate an ultra-potent microbial opsin and provide a platform for rational engineering of channelrhodopsins with improved properties that could expand the scale, depth, and precision of optogenetic experiments. Cryo-EM structures of the channelrhodopsin ChRmine in lipid nanodiscs.,Tucker K, Sridharan S, Adesnik H, Brohawn SG Nat Commun. 2022 Aug 17;13(1):4842. doi: 10.1038/s41467-022-32441-7. PMID:35977941 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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