Archaerhodopsin

Archaerhodopsin proteins are a family of retinal-containing photoreceptors found in the archaea genera Halobacterium and Halorubrum. Like the homologous bacteriorhodopsin (bR) protein, archaerhodopsins harvest energy from sunlight to pump H+ ions out of the cell, establishing a proton motive force that is used for ATP synthesis. They have some structural similarities to the mammalian G protein-coupled receptor protein rhodopsin, but are not true homologs.

Archaerhodopsins differ from bR in that the claret membrane, in which they are expressed, includes bacterioruberin, a second chromophore thought to protect against photobleaching. Also, bR lacks the omega loop structure observed at the N-terminus of the structures of several archaerhodopsins.

Mutants of Archaerhodopsin-3 (AR3) are used as tools in optogenetics for neuroscience research.[1]

Trimeric complex of archaerhodopsin-2 (PDB: 2EI4). The two gray planes indicate the hydrocarbon boundaries of the lipid bilayer and were calculated with the ANVIL algorithm.[2]
  1. ^ Flytzanis NC, Bedbrook CN, Chiu H, Engqvist MK, Xiao C, Chan KY, Sternberg PW, Arnold FH, Gradinaru V (2014). "Archaerhodopsin variants with enhanced voltage-sensitive fluorescence in mammalian and Caenorhabditis elegans neurons". Nature Communications. 5: 4894. Bibcode:2014NatCo...5.4894F. doi:10.1038/ncomms5894. PMC 4166526. PMID 25222271.
  2. ^ Postic, Guillaume; Ghouzam, Yassine; Guiraud, Vincent; Gelly, Jean-Christophe (2016). "Membrane positioning for high- and low-resolution protein structures through a binary classification approach". Protein Engineering, Design and Selection. 29 (3): 87–91. doi:10.1093/protein/gzv063. PMID 26685702.