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Photopsin
From Wikipedia, the free encyclopedia
(Redirected from Iodopsin)
Normalised absorption spectra of the three human
photopsins and of human rhodopsin
(dashed).
Photopsins (also known as Cone opsins) are
the photoreceptor proteins found in the
cone
cells of the retina that are the basis of color
vision. Iodopsin, the cone piment system in
chicken retina, is a close analo of the visual
purple rhodopsin that is used in niht vision.
Iodopsin consists of the protein component and a
bound chromophore, retinal.
Contents
• ! Function
• " #ypes
• $ %istory
• & 'ee also
• References
• *+ternal links
Function
psins are -n+ proteincoupled receptors of the retinylidene
protein family. Isomeri/ation of
!!cisretinal into alltransretinal by liht induces a
conformational chane in the protein that
activates photopsin and promotes its bindin to -
protein transducin, which triers a second
messener cascade.
https://en.wikipedia.org/w/index.php?title=Iodopsin&redirect=nohttps://en.wikipedia.org/wiki/Photoreceptor_cellhttps://en.wikipedia.org/wiki/Proteinhttps://en.wikipedia.org/wiki/Proteinhttps://en.wikipedia.org/wiki/Proteinhttps://en.wikipedia.org/wiki/Cone_cellhttps://en.wikipedia.org/wiki/Cone_cellhttps://en.wikipedia.org/wiki/Retinahttps://en.wikipedia.org/wiki/Retinahttps://en.wikipedia.org/wiki/Color_visionhttps://en.wikipedia.org/wiki/Rhodopsinhttps://en.wikipedia.org/wiki/Night_visionhttps://en.wikipedia.org/wiki/Chromophorehttps://en.wikipedia.org/wiki/Chromophorehttps://en.wikipedia.org/wiki/Retinalhttps://en.wikipedia.org/wiki/Retinalhttps://en.wikipedia.org/wiki/Photopsin#Functionhttps://en.wikipedia.org/wiki/Photopsin#Typeshttps://en.wikipedia.org/wiki/Photopsin#Historyhttps://en.wikipedia.org/wiki/Photopsin#See_alsohttps://en.wikipedia.org/wiki/Photopsin#Referenceshttps://en.wikipedia.org/wiki/Photopsin#External_linkshttps://en.wikipedia.org/w/index.php?title=Gn-x_protein-coupled_receptor&action=edit&redlink=1https://en.wikipedia.org/wiki/Retinylidene_proteinhttps://en.wikipedia.org/wiki/Isomerizationhttps://en.wikipedia.org/wiki/Lighthttps://en.wikipedia.org/wiki/G_proteinhttps://en.wikipedia.org/wiki/G_proteinhttps://en.wikipedia.org/wiki/Transducinhttps://en.wikipedia.org/wiki/Second_messengerhttps://en.wikipedia.org/wiki/Second_messengerhttps://en.wikipedia.org/wiki/Photoreceptor_cellhttps://en.wikipedia.org/wiki/Proteinhttps://en.wikipedia.org/wiki/Cone_cellhttps://en.wikipedia.org/wiki/Cone_cellhttps://en.wikipedia.org/wiki/Retinahttps://en.wikipedia.org/wiki/Color_visionhttps://en.wikipedia.org/wiki/Rhodopsinhttps://en.wikipedia.org/wiki/Night_visionhttps://en.wikipedia.org/wiki/Chromophorehttps://en.wikipedia.org/wiki/Retinalhttps://en.wikipedia.org/wiki/Photopsin#Functionhttps://en.wikipedia.org/wiki/Photopsin#Typeshttps://en.wikipedia.org/wiki/Photopsin#Historyhttps://en.wikipedia.org/wiki/Photopsin#See_alsohttps://en.wikipedia.org/wiki/Photopsin#Referenceshttps://en.wikipedia.org/wiki/Photopsin#External_linkshttps://en.wikipedia.org/w/index.php?title=Gn-x_protein-coupled_receptor&action=edit&redlink=1https://en.wikipedia.org/wiki/Retinylidene_proteinhttps://en.wikipedia.org/wiki/Isomerizationhttps://en.wikipedia.org/wiki/Lighthttps://en.wikipedia.org/wiki/G_proteinhttps://en.wikipedia.org/wiki/Transducinhttps://en.wikipedia.org/wiki/Second_messengerhttps://en.wikipedia.org/wiki/Second_messengerhttps://en.wikipedia.org/w/index.php?title=Iodopsin&redirect=no
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Types
0ifferent opsins differ in a few amino acids and absorb
liht at different wavelenths as
retinalbound piments.
Cone type Name Range Peak wavelength[1][2]
' (1N!'W) 2tritan2, 2cyanolabe2 3 &44544 nm
&"45&&4 nm
6 (1N!6W) 2deutan2, 2chlorolabe2 7 &45$4 nm $&5&
nm
8 (1N!8W) 2protan2, 2erythrolabe2 9 445:44 nm &5;4 nm
In humans there are $ different iodopsins (rhodopsin
analos) that contain the protein
piment comple+es photopsin I II and III.
#he $ types of iodopsins are called e!yth!ola"e(photopsin I
< retinal), chlo!ola"e(photopsin
II < retinal), and cyanola"e(photopsin III <
retinal).=$>
#hese photopsins have absorption ma+ima for
!ed =2erythr2red> #photopsin I$, g!een
=2chlor2reen> #photopsin II$, and "luish%violet liht
=2cyan2bluish violet> #photopsin III$.
&isto!y
-eore Wald received the !?: Nobel 1ri/e in 1hysioloy
or 6edicine for his e+periments in
the !?4s that showed the difference in absorbance by these
photopsins (see imae).=&>
'ee also
• Rhodopsins, the piment for monochromatic (scotopic) dark
vision.
• 6elanopsin, the piment which is used to control pupil si/es
and the sleep@wake cycle
• Aisual cycle, the chemistry of phototransduction
• Bolor blindness
Re(e!ences
!.
Wyszecki, Günther; Stiles, W.S. (1982. !olor Science"
!oncepts an# $etho#s, %uantitative
&ata an# 'ormulae (2n# e#.. e) *ork" Wiley Series in
+ure an# pplie# -ptics. S/ 0
31021043 .
5. W. G. 6unt (200. 7he 5epro#uction o !olour (4th e#..
!hichester :" Wiley
S9.
5ushton, W. . 6. (1 ?une 1944. @&ensitometry o
pi=ments in ro#s an# cones o normal
an# color #eective suABects@ (+&'. nvesti=ative
-phthalmolo=y 5 (C" 2CC21.
+$& >29483 . 5etrieve# 2004111.
https://en.wikipedia.org/wiki/Amino_acidhttps://en.wikipedia.org/wiki/Wavelengthhttps://en.wikipedia.org/wiki/Wavelengthhttps://en.wikipedia.org/wiki/Photopsin#cite_note-Wyszecki-1https://en.wikipedia.org/wiki/Photopsin#cite_note-2https://en.wikipedia.org/wiki/OPN1SWhttps://en.wikipedia.org/wiki/Nanometrehttps://en.wikipedia.org/wiki/Nanometrehttps://en.wikipedia.org/wiki/OPN1MWhttps://en.wikipedia.org/wiki/OPN1LWhttps://en.wikipedia.org/wiki/Humanshttps://en.wikipedia.org/wiki/Humanshttps://en.wikipedia.org/wiki/Photopsin#cite_note-3https://en.wikipedia.org/wiki/George_Waldhttps://en.wikipedia.org/wiki/Nobel_Prize_in_Physiology_or_Medicinehttps://en.wikipedia.org/wiki/Photopsin#cite_note-WaldNobelPrize-4https://en.wikipedia.org/wiki/Rhodopsinhttps://en.wikipedia.org/wiki/Melanopsinhttps://en.wikipedia.org/wiki/Visual_cyclehttps://en.wikipedia.org/wiki/Color_blindnesshttps://en.wikipedia.org/wiki/International_Standard_Book_Numberhttps://en.wikipedia.org/wiki/Special:BookSources/0-471-02106-7https://en.wikipedia.org/wiki/Special:BookSources/0-471-02106-7https://en.wikipedia.org/wiki/Special:BookSources/0-471-02106-7https://en.wikipedia.org/wiki/International_Standard_Book_Numberhttps://en.wikipedia.org/wiki/Special:BookSources/0-470-02425-9https://en.wikipedia.org/wiki/Special:BookSources/0-470-02425-9http://www.iovs.org/cgi/content/abstract/5/3/233http://www.iovs.org/cgi/content/abstract/5/3/233https://en.wikipedia.org/wiki/PubMed_Identifierhttps://www.ncbi.nlm.nih.gov/pubmed/5296487https://en.wikipedia.org/wiki/Amino_acidhttps://en.wikipedia.org/wiki/Wavelengthhttps://en.wikipedia.org/wiki/Photopsin#cite_note-Wyszecki-1https://en.wikipedia.org/wiki/Photopsin#cite_note-2https://en.wikipedia.org/wiki/OPN1SWhttps://en.wikipedia.org/wiki/Nanometrehttps://en.wikipedia.org/wiki/OPN1MWhttps://en.wikipedia.org/wiki/OPN1LWhttps://en.wikipedia.org/wiki/Humanshttps://en.wikipedia.org/wiki/Photopsin#cite_note-3https://en.wikipedia.org/wiki/George_Waldhttps://en.wikipedia.org/wiki/Nobel_Prize_in_Physiology_or_Medicinehttps://en.wikipedia.org/wiki/Photopsin#cite_note-WaldNobelPrize-4https://en.wikipedia.org/wiki/Rhodopsinhttps://en.wikipedia.org/wiki/Melanopsinhttps://en.wikipedia.org/wiki/Visual_cyclehttps://en.wikipedia.org/wiki/Color_blindnesshttps://en.wikipedia.org/wiki/International_Standard_Book_Numberhttps://en.wikipedia.org/wiki/Special:BookSources/0-471-02106-7https://en.wikipedia.org/wiki/Special:BookSources/0-471-02106-7https://en.wikipedia.org/wiki/International_Standard_Book_Numberhttps://en.wikipedia.org/wiki/Special:BookSources/0-470-02425-9http://www.iovs.org/cgi/content/abstract/5/3/233http://www.iovs.org/cgi/content/abstract/5/3/233https://en.wikipedia.org/wiki/PubMed_Identifierhttps://www.ncbi.nlm.nih.gov/pubmed/5296487
