8G3K

Cryo-EM imaging scaffold subunits A and B used to display KRAS G12C complex with GDP

Summary for 8G3K

• Entry DOI: 10.2210/pdb8g3k/pdb
• Related: 8G42
• EMDB information: 29700
• Descriptor: Cob_adeno_trans domain-containing protein, Cryo-EM imaging scaffold subunit B with DARPin - RCG-33 (2 entities in total)
• Functional Keywords: cryoem imaging scaffold, cancer, gtpase, structural protein
• Biological source: Thermoplasma acidophilum; More
• Total number of polymer chains: 2
• Total formula weight: 55625.84

Authors

Castells-Graells, R.,Sawaya, M.R.,Yeates, T.O. (deposition date: 2023-02-08, release date: 2023-08-09, Last modification date: 2023-09-27)

Primary citation

Castells-Graells, R.,Meador, K.,Arbing, M.A.,Sawaya, M.R.,Gee, M.,Cascio, D.,Gleave, E.,Debreczeni, J.E.,Breed, J.,Leopold, K.,Patel, A.,Jahagirdar, D.,Lyons, B.,Subramaniam, S.,Phillips, C.,Yeates, T.O.
Cryo-EM structure determination of small therapeutic protein targets at 3 angstrom -resolution using a rigid imaging scaffold.
Proc.Natl.Acad.Sci.USA, 120:e2305494120-e2305494120, 2023

PubMed Abstract: Cryoelectron microscopy (Cryo-EM) has enabled structural determination of proteins larger than about 50 kDa, including many intractable by any other method, but it has largely failed for smaller proteins. Here, we obtain structures of small proteins by binding them to a rigid molecular scaffold based on a designed protein cage, revealing atomic details at resolutions reaching 2.9 Å. We apply this system to the key cancer signaling protein KRAS (19 kDa in size), obtaining four structures of oncogenic mutational variants by cryo-EM. Importantly, a structure for the key G12C mutant bound to an inhibitor drug (AMG510) reveals significant conformational differences compared to prior data in the crystalline state. The findings highlight the promise of cryo-EM scaffolds for advancing the design of drug molecules against small therapeutic protein targets in cancer and other human diseases.

PubMed: 37669364
DOI: 10.1073/pnas.2305494120

Experimental method

ELECTRON MICROSCOPY (2.2 Å)