Sandbox Reserved 819: Difference between revisions
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Archaerhodopsin-2 (aR2) is a light-driven proton pump. The resulting proton gradient is subsequently converted into chemical energy. | Archaerhodopsin-2 (aR2) is a light-driven proton pump. The resulting proton gradient is subsequently converted into chemical energy. | ||
It is composed of 259 amino acids. 88% of this amino acid sequence is identical to the sequence of the archaerhodopsin. Moreover, there is 56% identity between this sequence and the sequence of the bacteriorhodopsin. <ref>PMID: 1654776</ref> | It is composed of 259 amino acids. 88% of this amino acid sequence is identical to the sequence of the archaerhodopsin. Moreover, there is 56% identity between this sequence and the sequence of the bacteriorhodopsin. <ref name="seq">PMID: 1654776</ref> | ||
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A molecule of α-D-mannose is covalently bound to one α-D-glucose and one β-D-galactose,thus creating a <scene name='56/568017/Glc-man-gal_and_rhodopsin/1'>glucose-mannose-galactose (GLC-MAN-GAL) ligand</scene>. There is one ligand by monomer. The glucose can create a covalent bond with the molecule of 2,3-Di-Phytanyl-Glycerol. | A molecule of α-D-mannose is covalently bound to one α-D-glucose and one β-D-galactose,thus creating a <scene name='56/568017/Glc-man-gal_and_rhodopsin/1'>glucose-mannose-galactose (GLC-MAN-GAL) ligand</scene>. There is one ligand by monomer. The glucose can create a covalent bond with the molecule of 2,3-Di-Phytanyl-Glycerol. | ||
==Comparison between the Archaerhodopsin-2 and the Bacteriorhodopsin== | |||
56% of the Archaeorhodopsin-2 sequence is identical to the Bacteriorhodopsin sequence.<ref name="seq">PMID: 1654776</ref> | |||
Most amino acids that play a role in the trimerization are not conserved between the two proteins. For instance, the counterparts of some hydrophobic residues of the Archaerhodopsin-2 (the one interacting with the polyene chain of the bacterioruberin) have a different volume. Another difference is the fact that the hydrophobic residues of the Archaerhodopsin-2 (responsible for the hydrogen bonds with the bacterioruberin) are replaced in the Bacteriorhodopsin by hydrophobic amino acids. | |||
However the global structures of Archaeorhodopsin-2 and Bacteriorhodopsin are really similar, especially at the level of the open space between the monomers. This similarity of structure forms the basis of several hypothesis concerning the mechanisms of the Archaeorhodopsin-2 <ref name="multiple">PMID:18082767</ref> | |||
