期刊
BIOCHEMISTRY
卷 56, 期 17, 页码 2338-2348出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.biochem.7b00165
关键词
-
资金
- Swiss National Science Foundation Doc.Mobility Fellowship [P1SKP3_158634]
- National Institutes of Health [EY025007, EY009339, EY027283]
- Arnold and Mabel Beckman Foundation
- Canadian Institute for Advanced Research
- Swiss National Science Foundation (SNF) [P1SKP3_158634] Funding Source: Swiss National Science Foundation (SNF)
Opsins comprise the protein component of light sensitive G protein-coupled receptors (GPCRs) in the retina of the eye that are responsible for the transduction of light into a biochemical signal. Here, we used hydrogen/deuterium (H/D) exchange coupled with mass spectrometry to map conformational changes in green cone opsin upon light activation. We then compared these findings with those reported for rhodopsin. The extent of H/D exchange in green cone opsin was greater than in rhodopsin in the dark and bleached states, suggesting a higher structural heterogeneity for green cone opsin. Further analysis revealed that green cone opsin exists as a dimer in both dark (inactive) and bleached (active) states, and that the predicted glycosylation sites at N-32 and N-34 are indeed glycosylated. Comparison of deuterium uptake between inactive and active states of green cone opsin also disclosed a reduced solvent accessibility of the extracellular N-terminal region and an increased accessibility of the chromophore binding site. Increased H/D exchange at the extracellular side of transmembrane helix four (TM4) combined with an analysis of sequence alignments revealed a conserved Pro-Pro motif in extracellular loop 2 (EL2) of monostable visual GPCRs. These data present new insights into the locus of chromophore release at the extracellular side of TM4 and TM5 and provide a foundation for future functional evaluation.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据