What is "proteorhodopsin"

n. (context protein English) Any of several proteins, that are light-dependent proton pumps, found in marine bacteria.

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.

Its name is derived from the Ancient Greek Πρωτεύς ( Proteus), an early sea god mentioned by Homer as " Old Man of the Sea", Ῥόδος (rhódon) for " rose", due to its pinkish color, and ὄψις ( opsis) for "sight". Some members of the family, Homologous rhodopsin-like pigments, i.e. bacteriorhodopsin (of which there are more than 800 types) have Sensory Functions like opsins, integral for visual phototransduction. Many of these sensory functions are unknown – for example, the function of Neuropsin in the human retina. Members are known to have different absorption spectra including green and blue visible light.