Structural insights into spectral tuning and retinal exchange in cone visual pigments
Abstract
Color vision in catarrhine primates relies on red-, green-, and blue-sensitive cone pigments that share an 11- cis -retinal chromophore but differ in absorption maxima. Red and green pigments arose by recent gene duplication and differ at only a few residues. Here, we report cryo–electron microscopy structures of red and green cone pigments from the cynomolgus macaque ( Macaca fascicularis ) integrated with low-temperature vibrational spectroscopy and quantum mechanical and molecular mechanical modeling. The red-green spectral shift is dominated by threonine 285, the hydroxyl dipole of which modulates chromophore electrostatics, whereas steric effects appear modest. We also identified membrane-facing lateral openings in cone pigments but not in inactive rhodopsin. Comparisons with active-state structures suggest activation-dependent gating, and mutational and spectroscopic analyses support a role for this opening in retinal uptake and rapid pigment regeneration.
Article Details
Journal Info
Science
American Association for the Advancement of Science
Authors (19)
Sayaka Ohashi
Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan.
Kota Katayama
Asato Kojima
Research Center for Advanced Science and Technology, The University of Tokyo, Meguro, Tokyo, Japan.
Xuchun Yang
Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy.
Masahiro Fukuda
Filippo Sacchetta
Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy.
Ryoji Suno
Kansai Medical University, Hirakata, Japan.
Yukihiko Sugita
Institute for Life and Medical Sciences, Kyoto University, Kyoto, Japan.
Nipawan Nuemket
Japan Synchrotron Radiation Research Institute, Harima, Japan.
Suhyang Kim
Research Center for Advanced Science and Technology, The University of Tokyo, Meguro, Tokyo, Japan.
Kazuhiro Kobayashi
Hiroo Imai
Institute for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Japan.
So Iwata
Eriko Nango
RIKEN Spring-8 Center, Harima, Japan.
Takuya Kobayashi
Kansai Medical University, Hirakata, Japan.
Takeshi Noda
Institute for Life and Medical Sciences, Kyoto University, Kyoto, Japan.
Massimo Olivucci
Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy.
Hideaki E. Kato
Hideki Kandori