111724-05-1Relevant articles and documents
8,16- And 8,18-methanobacteriorhodopsin. Synthesis and spectroscopy of 8,16- and 8,18-methanoretinal and their interaction with bacterioopsin
Steen, R. van der,Biesheuvel, P. L.,Erkelens, C.,Mathies, R. A.,Lugtenburg, J.
, p. 83 - 93 (2007/10/02)
8,16- And 8,18-methanoretinal with a locked 6-s-trans and a 6-s-cis conformation have been synthesized and characterized.Their 9-Z and 13-Z isomers could also be prepared, in contrast to the 11-Z. 8,16-Methanoretinal easily binds with bacterioopsin (bO) to form a bacteriorhodopsin analogue which closely resembles natural bacteriorhodopsin (bR) (λmax, light-dark adaptation and proton pump action).The interaction of 8,18-methanoretinal with bO is complex.These findings give additional support to the fact that in bR the chromophore occurs in the planar 6-s-trans conformation.Approximately 1200 cm-1 of the opsin shift in bR (5100 cm-1) arises because the chromophore changes upon binding to the protein from a 40 deg twisted 6-s-cis to a planar 6-s-trans conformation.Both 8,16- and 8,18-methano bR have a ca. 3900 cm-1 opsin shift, since the C6-C7 conformation does not allow protein-induced changes.This is consistent with the idea that the opsin shift is mainly due to the perturbation of the Schiff base region.
