Role of Retinal Isomerizations and Rotations in the Photocycle of Bacteriorhodopsin

Amnon Albeck, Noga Friedman, Mordechai Sheves, Michael Ottolenghi

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Artificial bacteriorhodopsin (bR) pigments based on synthetic retinal analogues with selectively blocked single and double bonds were prepared. It was shown that rotations around single bonds C12-C13 and C10-C11 and isomerizations of C11=C12 and C9=C10 are not required either for initiating the photocycle of all-trans-bR or for forming its M412 intermediate. The results are discussed in light of mechanisms for the primary event (based on the C13=C14 isomerization) involving a concerted double-bond and single-bond rotation around adjacent C,C bonds. Similarly, the photoreaction of the 13-cis isomer of bacteriorhodopsin does not require isomerization about the C11=C12 double bond or rotation around C12-C13. It is also shown that 13-cis ⇔ all-trans (light-dark adaptation) reaction of bacteriorhodopsin does not involve additional rotations or isomerizations involving the C9-C13 section of the molecule.

Original languageEnglish
Pages (from-to)4614-4618
Number of pages5
JournalJournal of the American Chemical Society
Volume108
Issue number15
DOIs
StatePublished - 1986
Externally publishedYes

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