6OY9

Structure of the Rhodopsin-Transducin Complex

Summary for 6OY9

• Entry DOI: 10.2210/pdb6oy9/pdb
• EMDB information: 20222 20223
• Descriptor: Gt-alpha/Gi1-alpha chimera, Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1, Guanine nucleotide-binding protein G(T) subunit gamma-T1, ... (5 entities in total)
• Functional Keywords: gpcr, g protein, complex, signaling protein
• Biological source: Bos taurus (Bovine); More
• Total number of polymer chains: 4
• Total formula weight: 127273.53

Authors

Gao, Y.,Hu, H.,Ramachandran, S.,Erickson, J.W.,Cerione, R.A.,Skiniotis, G. (deposition date: 2019-05-14, release date: 2019-07-24, Last modification date: 2019-12-04)

Primary citation

Gao, Y.,Hu, H.,Ramachandran, S.,Erickson, J.W.,Cerione, R.A.,Skiniotis, G.
Structures of the Rhodopsin-Transducin Complex: Insights into G-Protein Activation.
Mol.Cell, 75:781-, 2019

PubMed Abstract: Rhodopsin (Rho), a prototypical G-protein-coupled receptor (GPCR) in vertebrate vision, activates the G-protein transducin (G) by catalyzing GDP-GTP exchange on its α subunit (Gα). To elucidate the determinants of G coupling and activation, we obtained cryo-EM structures of a fully functional, light-activated Rho-G complex in the presence and absence of a G-protein-stabilizing nanobody. The structures illustrate how G overcomes its low basal activity by engaging activated Rho in a conformation distinct from other GPCR-G-protein complexes. Moreover, the nanobody-free structures reveal native conformations of G-protein components and capture three distinct conformers showing the Gα helical domain (αHD) contacting the Gβγ subunits. These findings uncover the molecular underpinnings of G-protein activation by visual rhodopsin and shed new light on the role played by Gβγ during receptor-catalyzed nucleotide exchange.

PubMed: 31300275
DOI: 10.1016/j.molcel.2019.06.007

Experimental method

ELECTRON MICROSCOPY (3.9 Å)