Free backbone carbonyls mediate rhodopsin activation

Naoki Kimata, Andreyah Pope, Omar B. Sanchez-Reyes, Markus Eilers, Chikwado A. Opefi, Martine Ziliox, Philip J. Reeves, Steven O. Smith*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Conserved prolines in the transmembrane helices of G-protein-coupled receptors (GPCRs) are often considered to function as hinges that divide the helix into two segments capable of independent motion. Depending on their potential to hydrogen-bond, the free C=O groups associated with these prolines can facilitate conformational flexibility, conformational switching or stabilization of the receptor structure. To address the role of conserved prolines in family A GPCRs through solid-state NMR spectroscopy, we focus on bovine rhodopsin, a GPCR in the visual receptor subfamily. The free backbone C=O groups on helices H5 and H7 stabilize the inactive rhodopsin structure through hydrogen-bonds to residues on adjacent helices. In response to light-induced isomerization of the retinal chromophore, hydrogen-bonding interactions involving these C=O groups are released, thus facilitating repacking of H5 and H7 onto the transmembrane core of the receptor. These results provide insights into the multiple structural and functional roles of prolines in membrane proteins.

Original languageEnglish
Pages (from-to)738-743
Number of pages6
JournalNature Structural and Molecular Biology
Issue number8
Publication statusPublished - 2016 Aug 1
Externally publishedYes

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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