Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 109, Issue 1, Pages 119-124Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1114089108
Keywords
constitutive activity; GPCRs; light-activated; rhodopsin
Categories
Funding
- Swiss National Science Foundation (SNSF) [31003A_132815]
- ETH Zurich
- National Center for Competence in Research
- National Institutes of Health [EY007965]
- MRC [MC_U105197215] Funding Source: UKRI
- Swiss National Science Foundation (SNF) [31003A_132815] Funding Source: Swiss National Science Foundation (SNF)
- Medical Research Council [MC_U105197215] Funding Source: researchfish
Ask authors/readers for more resources
G protein-coupled receptors (GPCR) are seven transmembrane helix proteins that couple binding of extracellular ligands to conformational changes and activation of intracellular G proteins, GPCR kinases, and arrestins. Constitutively active mutants are ubiquitously found among GPCRs and increase the inherent basal activity of the receptor, which often correlates with a pathological outcome. Here, we have used the M257Y(6.40) constitutively active mutant of the photoreceptor rhodopsin in combination with the specific binding of a C-terminal fragment from the G protein alpha subunit (G alpha CT) to trap a light activated state for crystallization. The structure of the M257Y/G alpha CT complex contains the agonist all-trans-retinal covalently bound to the native binding pocket and resembles the G protein binding metarhodopsin-II conformation obtained by the natural activation mechanism; i.e., illumination of the prebound chromophore 11-cis-retinal. The structure further suggests a molecular basis for the constitutive activity of 6.40 substitutions and the strong effect of the introduced tyrosine based on specific interactions with Y223(5.58) in helix 5, Y306(7.53) of the NPxxY motif and R135(3.50) of the E(D)RY motif, highly conserved residues of the G protein binding site.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available