Palmitoylation of bovine opsin and its cysteine mutants in COS cells

Karnik, S. S. ; Ridge, K. D. ; Bhattacharya, S. ; Khorana, H. G. (1993) Palmitoylation of bovine opsin and its cysteine mutants in COS cells Proceedings of the National Academy of Sciences of the United States of America, 90 (1). pp. 40-44. ISSN 0027-8424

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Official URL: http://www.pnas.org/content/90/1/40.abstract?sid=b...

Abstract

Previously, bovine rhodopsin has been shown to be palmitoylated at cysteine residues 322 and 323. Here we report on palmitoylation of bovine opsin in COS-1 cells following expression of the synthetic wild-type opsin gene and several of its cysteine mutants in the presence of [3H]palmitic acid. Two moles of palmitic acid are introduced per wild-type opsin molecule in thioester linkages. Palmitoylation is abolished when both Cys-322 and Cys-323 are replaced by serine residues. Replacement of Cys-322 by serine prevents palmitoylation at Cys-323, whereas replacement of the latter with serine allows palmitoylation at Cys-322. Opsin mutants that evidently do not contain a Cys-110/Cys-187 disulfide bond and presumably remain in the endoplasmic reticulum are not palmitoylated. Replacement of Cys-140 or Cys-185 reduces the extent of palmitoylation of the opsin. Lack of palmitoylation at Cys-322 and/or Cys-323 does not affect 11-cis-retinal binding, absorption maximum or extinction coefficient of the chromophore, the bleaching behavior of the chromophore, or the light-dependent binding and activation of transducin. Mutants containing serine substitutions at Cys-140 or Cys-323 showed reduced light-dependent phosphorylation by rhodopsin kinase.

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Source:Copyright of this article belongs to National Academy of Sciences, USA.
ID Code:21028
Deposited On:20 Nov 2010 09:20
Last Modified:17 May 2016 05:16

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