7JSN

Structure of the Visual Signaling Complex between Transducin and Phosphodiesterase 6

Summary for 7JSN

• Entry DOI: 10.2210/pdb7jsn/pdb
• EMDB information: 22458
• Descriptor: Rod cGMP-specific 3',5'-cyclic phosphodiesterase subunit alpha, Rod cGMP-specific 3',5'-cyclic phosphodiesterase subunit beta, Guanine nucleotide-binding protein G(t) subunit alpha-1, Guanine nucleotide-binding protein G(i) subunit alpha-1 chimera, ... (9 entities in total)
• Functional Keywords: g protein, g protein-effector complex, transducin, phosphodiesterase 6, phototransduction, gpcr signaling, signaling protein
• Biological source: Bos taurus (Bovine); More
• Total number of polymer chains: 6
• Total formula weight: 304609.37

Authors

Gao, Y.,Eskici, G.,Ramachandran, S.,Skiniotis, G.,Cerione, R.A. (deposition date: 2020-08-15, release date: 2020-10-21, Last modification date: 2025-05-14)

Primary citation

Gao, Y.,Eskici, G.,Ramachandran, S.,Poitevin, F.,Seven, A.B.,Panova, O.,Skiniotis, G.,Cerione, R.A.
Structure of the Visual Signaling Complex between Transducin and Phosphodiesterase 6.
Mol.Cell, 80:237-, 2020

PubMed Abstract: Heterotrimeric G proteins communicate signals from activated G protein-coupled receptors to downstream effector proteins. In the phototransduction pathway responsible for vertebrate vision, the G protein-effector complex is composed of the GTP-bound transducin α subunit (Gα·GTP) and the cyclic GMP (cGMP) phosphodiesterase 6 (PDE6), which stimulates cGMP hydrolysis, leading to hyperpolarization of the photoreceptor cell. Here we report a cryo-electron microscopy (cryoEM) structure of PDE6 complexed to GTP-bound Gα. The structure reveals two Gα·GTP subunits engaging the PDE6 hetero-tetramer at both the PDE6 catalytic core and the PDEγ subunits, driving extensive rearrangements to relieve all inhibitory constraints on enzyme catalysis. Analysis of the conformational ensemble in the cryoEM data highlights the dynamic nature of the contacts between the two Gα·GTP subunits and PDE6 that supports an alternating-site catalytic mechanism.

PubMed: 33007200
DOI: 10.1016/j.molcel.2020.09.013

Experimental method

ELECTRON MICROSCOPY (3.2 Å)