Proteorhodopsin
![Holoenzyme (Green) with helicies A-G labeled (purple) as well as Retinal ligand (orange)](/Images/godic/202502/04/PR_surface_visualization_-_ELViture_April_20161541.png")
![2L6x In-Active-Site Cartoon Color Coded and Labeled Visualization, D and E Helicies hidden for vantage, Retinal ligand binding site](/Images/godic/202502/04/In-Active-Site_Visualization,_D_and_E_Helicies_hidden_for_vantag._ELViture_4-16_1541.png")
![Visualization of the retinal bound active site of the 2L6X protein structure of pRhodopsin, residues color coded and labeled by activity, ligand is orange.](/Images/godic/202502/04/2L6X_Active_Site_Visualization_E.Vitureira1541.png")
![](/Images/godic/202502/04/Proteorhodopsin_Cartoon_Visualization_E.Vitureira_4-161541.png")
Proteorhodopsin (also known as pRhodopsin) is a family of over 50 photoactive retinylidene proteins, a larger family of transmembrane proteins that use retinal as a chromophore for light-mediated functionality, in this case, a proton pump. Some homologues exist as pentamers or hexamers. pRhodopsin is found in marine planktonic bacteria, archaea and eukaryotes (protae), but was first discovered in bacteria.