Bacteriorhodopsin analogue from anthryl chromophores

Abstract

ANIL K. SINGH and MITA ROY. Can. J. Chem. 68, 383 (1990). Preparation and properties of the bacteriorhodopsin (bR) analogue having the 3,7-dimethyl-9-(9-anthryl)-2E,4E,6E,8E-nonatetraenal(12) chromophore is described. Synthesis of the chromophore has been achieved by successive introduction of Cs units to 9-anthraldehyde (3) via the Homer reaction. The all-trans chromophore has been characterized by its ultraviolet-visible and 'H nuclear magnetic resonance spectra. Incubation of 12 with bacterioopsin suspension (prepared by photobleaching of bR isolated from Halobacterium halobium) at ambient temperature in the dark gave the new bR analogue 15, which showed an absorption band at 545 nm, and an opsin shift of 5575 cm-I. The new pigment is stable to hydroxyl amine in the dark. It showed light-dark adaptation with the light-adapted form absorbing at a slightly red-shifted value of 550 nm. All-trans-retinal did not replace the anthryl chromophore in competitive bindings. Photolysis of the bR analogue 15, followed by difference spectrophotometric analysis, indicated formation of a photoproduct with an absorption band near 400 nm. The results are discussed in terms of the stereoelectronic requirements of the bR reaction centre.Key words: bacteriorhodopsin (bR), retinal analogue, reconstitution, opsin shift (OS), external point charge model (EPC).ANIL K. SINGH et MITA ROY. Can. J. Chem. 68, 383 (1990). On dkcrit la prkparation et les propriktks d'un analogue de la bactkriorhodopsine (bR) posskdant le chromophore 3,7-dimkthyl-9-(9-anthryl)-2E,4E,6E,8E-nonatktrabnal(lZ). On a rkalisk la synthese du chromophore en faisant appel a la rkaction de Homer pour introduire des unites successives en C5 sur le 9-anthraldkhyde (3). On a 6tabli le caractere completement trans du chromophore l'aide de donnkes d'UV-VIS et de RMN du I3c. L'incubation, a la tempkrature ambiante et en I'absence de lumiere, du composk 12 avec une suspension de bactkrioopsine (preparke par photoblanchiment d'une bR isolCe a partir de Halobacterium halobium) foumit le nouvel analogue 15 de la bR qui prksente une bande d'absorption h 545 nm et un dkplacement opsine de 5575 cm-I. Le nouveau pigment ne rkagit pas avec I'hydroxylamine, en I'absence de lumibre. I1 prksente une adaptation de la lumihre a la noirceur; la forme adaptke a la lumiere absorbe une valeur de 550 nm, qui est lkgbrement dCplacCe vers le rouge. Le rktinal completement trans ne remplace pas le chromophore anthryle dans les sites oh ils sont en compCtition. La photolyse de la bR analogue 15, suivie par une analyse spectrophotomktrique diffkrentielle, indique qu'il y a formation d'un photo-produit posskdant une bande d'absorption pres de 400 nm. On discute des rksultats en fonction des facteurs stkrkoklectroniques inhkrents au centre rkactionnel de la bR.Mots clks : bactkriorhodopsine (bR), analogue rktinal, reconstitution, dkplacement opsine, modble de point-charge externe.[Traduit par la revue]

Dramatic solvent and concentration dependence in the reaction of (anthracen-9-yl)methanamines with suitable electron-deficient acetylenes

“…As expected, product distribution changed under different conditions. However, a few products arising through either single electron transfer mediated transformations such as 9‐methylanthracene ( 7 ), 9‐anthraldehyde ( 6 ), 1,2‐bis(9‐anthracenyl)ethane ( 8 ) and lepidopterene ( 9 ) or through reaction with adventitious oxygen such as 9,10‐anthraquinone ( 5 ) were common in all reactions (Chart ). In most cases, acetylenes underwent oligomerization to intractable residues.…”

(Anthracen-9-yl)methyl sulfides as a mechanistic probe for chemical as well as photochemical electron-transfer reactions

“…Various fractions were collected and analyzed using spectroscopic measurements. The products formed were identified as 9-anthraldehyde (3), 63 9,10-anthraquinone (6), 64 9-methylanthracene (12), 65 1,2-bis(9-anthracenyl)ethane (13), [66][67][68][69] lepidopterene (14), 66,[70][71][72][73][74] biplanene (15), [75][76][77] anthrone (16) 78 along with products arising through the S-alkyl residues present in parent anthracenemethyl sulfides. Common products formed in the photoirradiation of (anthracen-9-yl)methyl sulfides 1a-f are shown in Chart 2 and details of all the products isolated are presented in Scheme 3.…”

Development of Bacteriorhodopsin Analogues and Studies of Charge Separated Excited States in the Photoprocesses of Linear Polyenes†

“…Some bR‐analogues prepared by different researchers are given in Table 2. We have prepared bR analogues based on iodophenyl (60), anthryl (61), azobenzene (62), diphenylpolyene (59) and indolyl (63) retinal analogues. These are characterized for their absorption behavior, opsin shift, competitive binding, fluorescence emission, light‐induced pH activity and chromophore photochemistry.…”

“…In 1990, our group (61), and in 1999, Crouch and her co‐workers (73) synthesized anthracene ( e.g. bRa‐16 ) and pyrylretinal ( e.g.…”