May 2005
Volume 46, Issue 13
ARVO Annual Meeting Abstract  |   May 2005
The Role of the Conserved Counterion Residue in a UV Cone Pigment
Author Affiliations & Notes
  • M. Kono
    Ophthalmology, Med Univ South Carolina, Charleston, SC
  • Footnotes
    Commercial Relationships  M. Kono, None.
  • Footnotes
    Support  NIH Grant EY013748
Investigative Ophthalmology & Visual Science May 2005, Vol.46, 2987. doi:
  • Views
  • Share
  • Tools
    • Alerts
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      M. Kono; The Role of the Conserved Counterion Residue in a UV Cone Pigment . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2987.

      Download citation file:

      © ARVO (1962-2015); The Authors (2016-present)

  • Supplements

Abstract: : In rhodopsin, the 11–cis retinal chromophore is bound to Lys296 via a protonated Schiff base linkage. The resulting positive charge in the transmembrane domain is offset by the highly conserved negatively charged Glu113 in helix 3. Recent work indicates that UV cone pigments have retinal bound as an unprotonated Schiff base, and the absence of a positive charge yields the blue–shifted UV absorption properties. Nevertheless, Glu is conserved in all vertebrate UV pigments cloned to date. Purpose:This study aims to ascertain the role of this conserved Glu. Methods: The wild–type and mutant salamander UV cone pigments were expressed in COS cells. In the UV pigment, Glu108 corresponds to Glu113 of bovine rhodopsin. This residue was replaced with Gln, and the absorption spectrum and the protein’s ability to activate transducin was assessed. Results: The absorption maximum of the Glu to Gln mutant is blue–shifted about 6 nm relative to the wild–type. The apoprotein of the mutant is more constitutively active than the wild–type opsin and is inactivated by 11–cis retinal. Conclusions: The data suggest that Glu108 is conserved not to be a counterion to the Schiff base but to maintain a relatively inactive aprotein.

Keywords: color pigments and opsins • protein structure/function 

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.