#bacteriorhodopsin

[earthstory]

Pink Lakes Halobacteria (a form of Archea) thrive in water bodies with high salt content (at an optimal concentration of 20-25%), to the extent they are considered extremophiles. Crucially to Halobacteria’s ‘pink-ness’ they contain a pigment called bacteriorhodopsin that is used to absorb light in photosynthesis. However, with large blooms of halobacteria lakes can appear red or pink, as seen in the photo above.

The classic example of a lake showing this feature is Pink Lake (also known as Hiller Lake) in Western Australia; which is affected by Halobacteria cutirubrum and Dunaliella salina. The photo does not show a lake, though; instead it shows the salt ponds in San Francisco Bay. These show the same bright colouring due to the same halobacteria as discussed earlier. The green pools contrast the pink ones both in colour and salinity, as the green has low salinity that allows green algae to thrive. The orange pool, however, holds its colour due to Brine shrimp, which generally occur in mid-salinities. ~SA Image: http://bit.ly/1LNYb1p by Grombo Hellier Lake: http://bit.ly/1Msw2xB

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Photocycle of Bacteriorhodopsin

After the absorption of a photon by retinal, this molecule transmits the stimulation to the whole protein. The isomerization of the retinal after the stimulus, besides the contacts with the residues of the RBP, transduces the signal, through the different helices, from the middle of the protein to the cytoplasmic and extracellular side of the protein. The final result of this process yields the…

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Bacteriorhodopsin

In a cell, be it prokaryotic or eukaryotic, there are plenty of functions to perform. Most of which are carried out by proteins. Depending on the location, proteins can be soluble or transmembrane or amphitropic. The functions of transmembrane proteins range from signal transduction, ion channels, energy transduction, structural role to even cell recognition, among others. If one protein that can…

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