Sandbox Reserved 819: Difference between revisions
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Archaerhodopsin-2 consists of the protein moiety rhodopsin and a reversibly covalently bound cofactor, retinal. The protein <scene name='56/568017/Rhodopsin/1'>rhodopsin</scene> has 7 transmembrane alpha helices, embedded in the plasma membrane, whose helices are connected each other by protein loops. It binds retinal, C20 H28 O , a photoreactive chromophore, located in a central pocket on the seventh helix at the <scene name='56/568017/Lysine_221/1'>lysine residue 221</scene> by covalent bond. Retinal is a polyene chromophore and allows to convert light into metabolic energy. It absorbs visible light maximally at 550-570 nm. | Archaerhodopsin-2 consists of the protein moiety rhodopsin and a reversibly covalently bound cofactor, retinal. The protein <scene name='56/568017/Rhodopsin/1'>rhodopsin</scene> has 7 transmembrane alpha helices, embedded in the plasma membrane, whose helices are connected each other by protein loops. It binds retinal, C20 H28 O , a photoreactive chromophore, located in a central pocket on the seventh helix at the <scene name='56/568017/Lysine_221/1'>lysine residue 221</scene> by covalent bond. Retinal is a polyene chromophore and allows to convert light into metabolic energy. It absorbs visible light maximally at 550-570 nm. | ||
It catches a photon, leading to a conformational change of the rhodopsin. This is an isomerization of 11-cis-retinal into all-trans-retinal. Retinal binds covalently to the lysine 221 on the transmembrane helix nearest the C-terminus of the protein through a Schiff base linkage. Formation of the Schiff base linkage involves removing the oxygen atom from retinal and two hydrogen atoms from the free amino group of lysine, giving H2O. Retinylidene is the divalent group formed by removing the oxygen atom from retinal, and so opsins is called retinylidene proteins. A Schiff base is a compound with a functional group made up of a carbon-nitrogen double bond with a nitrogen atom connected to an aryl or alkyl group, not hydrogen. Schiff bases in a broad sense have the general formula R1-R2-C=N-R3, where R is an organic side chain. In this definition, Schiff base is synonymous with azomethine. The chain on the nitrogen makes the Schiff base a stable imine. A Schiff base derived from an aniline, where R3 is a phenyl or a substituted phenyl. | It catches a photon, leading to a conformational change of the rhodopsin. This is an isomerization of 11-cis-retinal into all-trans-retinal. Retinal binds covalently to the lysine 221 on the transmembrane helix nearest the C-terminus of the protein through a Schiff base linkage. Formation of the Schiff base linkage involves removing the oxygen atom from retinal and two hydrogen atoms from the free amino group of lysine, giving H2O. Retinylidene is the divalent group formed by removing the oxygen atom from retinal, and so opsins is called retinylidene proteins. A Schiff base is a compound with a functional group made up of a carbon-nitrogen double bond with a nitrogen atom connected to an aryl or alkyl group, not hydrogen. Schiff bases in a broad sense have the general formula R1-R2-C=N-R3, where R is an organic side chain. In this definition, Schiff base is synonymous with azomethine. The chain on the nitrogen makes the Schiff base a stable imine. A Schiff base derived from an aniline, where R3 is a phenyl or a substituted phenyl. | ||
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The bacterioruberin, C50 H76 O4, is a 50 carbon carotenoid pigment which give a red color to the membrane . It binds to: the B chain thanks a hydrogen bond with the <scene name='56/568017/Threonine_112/1'>Threonine 112</scene> and the <scene name='56/568017/Tyrosine/1'>Tyrosine 156</scene>; the D chain thanks a hydrogen bond with the Tyrosine 156; the E chain thanks a hydrogen bond with the Tyrosine 156 and the HOH 304. | |||
==The 2,3-di-phytanyl-glycerol== | ==The 2,3-di-phytanyl-glycerol== | ||
