Biomaterial Database

Retinal location in purple membrane of Halobacterium halobium: a neutron diffraction study of membranes labelled in vivo with deuterated retinal. 1984

J S Jubb, and D L Worcester, and H L Crespi, and G Zaccaï

Purple membranes were prepared by growing Halobacterium halobium in a medium containing nicotine (which inhibits biosynthesis of retinal) and the oxidation products of fully deuterated beta-carotene. This allowed the in vivo incorporation of deuterated retinal into the membranes. The labelled membranes were crystalline and isomorphous with native membrane as determined by X-ray diffraction, and their optical absorption spectra were very similar. Neutron diffraction data for the two dimensional in-plane lattice from labelled and native membranes were analysed by difference Fourier and direct methods to 8.6 A resolution. The difference Fourier shows the retinal to be located in the centre of the bacteriorhodopsin molecule. The best fit to the data was obtained with the projection of retinal as a 10 A long rod forming an angle of -40 degrees +/- 10 degrees with the x axis centred at x = -0.19 +/- 0.02, y = -0.35 +/- 0.02 in fractional unit cell coordinates. The main peak in the difference Fourier map is at x = -0.17, y = -0.33.

UI	MeSH Term	Description	Entries
D002338	Carotenoids	The general name for a group of fat-soluble pigments found in green, yellow, and leafy vegetables, and yellow fruits. They are aliphatic hydrocarbons containing 4 terpene subunits.	Carotenes,Carotenoid,Tetraterpene Derivatives,Tetraterpenes,Carotene,Derivatives, Tetraterpene
D006217	Halobacterium	A genus of HALOBACTERIACEAE whose growth requires a high concentration of salt. Binary fission is by constriction.
D001436	Bacteriorhodopsins	Rhodopsins found in the PURPLE MEMBRANE of halophilic archaea such as HALOBACTERIUM HALOBIUM. Bacteriorhodopsins function as an energy transducers, converting light energy into electrochemical energy via PROTON PUMPS.	Bacteriorhodopsin
D012172	Retinaldehyde	A diterpene derived from the carotenoid VITAMIN A which functions as the active component of the visual cycle. It is the prosthetic group of RHODOPSIN (i.e., covalently bonded to ROD OPSIN as 11-cis-retinal). When stimulated by visible light, rhodopsin transforms this cis-isomer of retinal to the trans-isomer (11-trans-retinal). This transformation straightens-out the bend of the retinal molecule and causes a change in the shape of rhodopsin triggering the visual process. A series of energy-requiring enzyme-catalyzed reactions convert the 11-trans-retinal back to the cis-isomer.	11-trans-Retinal,3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-Nonatetraenal,Axerophthal,Retinal,Retinene,Retinyl Aldehydde,Vitamin A Aldehyde,all-trans-Retinal,11-cis-Retinal,11 cis Retinal,11 trans Retinal,Aldehydde, Retinyl,Aldehyde, Vitamin A,all trans Retinal
D012176	Retinoids	A group of tetraterpenes, with four terpene units joined head-to-tail. Biologically active members of this class are used clinically in the treatment of severe cystic ACNE; PSORIASIS; and other disorders of keratinization.	Retinoid
D013057	Spectrum Analysis	The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Spectroscopy,Analysis, Spectrum,Spectrometry