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Function
Transducin (TDN) is a heterotrimeric G protein containing 3 chains: α, β and γ which are organized in two subunits: α and βγ[1]. TDN is involved in phototransduction. The absorption of a photon by retinal causes a change in the conformation of rhodopsin into metarhodopsin II. The latter causes activation of TDN. Upon TDN activation the GDP bound to its α subunit is exchanged for the GTP from the cytoplasm. Deactivation of TDN occurs when the GTP bound to the α subunit is hydrolyzed to GDP. Phosducin binds to the βγ subunit of TND preventing its re-association with the α subunit.
Disease
Congenital stationary night blindness (Nougaret disease) is caused by a mutation in TDN α subunit[2].
- ↑ Lerea CL, Bunt-Milam AH, Hurley JB. Alpha transducin is present in blue-, green-, and red-sensitive cone photoreceptors in the human retina. Neuron. 1989 Sep;3(3):367-76. PMID:2534964
- ↑ Dryja TP, Hahn LB, Reboul T, Arnaud B. Missense mutation in the gene encoding the alpha subunit of rod transducin in the Nougaret form of congenital stationary night blindness. Nat Genet. 1996 Jul;13(3):358-60. PMID:8673138 doi:https://dx.doi.org/10.1038/ng0796-358
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3D structures of transducin
Updated on 27-November-2016
{"openlevels":0}
- Transducin-α
- 1tnd – bTDN + GTPγS - bovine
- 1tag – bTDN + GDP
- 3v00 – b/ratTDN + GDP
- 1tad – bTDN + GDP + AlF4
- 1fqk – bTDN + RGS9 + GDP + AlF4
- 1fqj – bTDN + RGS9 + GMP-PDE γ + GDP + AlF4
- Transducin-βγ
- 1tbg – bTDN
- 2trc, 1a0r, 1b9x, 1b9y – bTDN + phosducin
- 1omw, 3cik – bTDN + G-protein coupled receptor kinase 2
- 3v5w – bTDN (mutant) + G-protein coupled receptor kinase 2
- 3psc, 3pvu, 3pvw, 4mk0 – bTDN + β-adrenergic receptor kinase 1
- 2bcj – bTDN (mutant) + β-adrenergic receptor kinase 1
- 3uzs – bTDN + β-adrenergic receptor kinase 1 + RNA
- 3krw, 3krx – bTDN + G-protein coupled receptor kinase 2 + inhibitor
- 1xhm – bTDN + peptide
- 4kfm – hTDN + G-protein activated inward rectifier K+ channel
- Transducin-α+βγ
- 1got – bTDN + GDP
- 1gg2 – rTDN + GDP - rat
- 1gp2 – rTDN (mutant) + GDP
- 3ah8 – bTDN (mutant) + GDP + inhibitor
- 3sn6 – bTDN (mutant) + endolysine + antibody fragment
References
