36OI

Tri-complex of Compound 1, KRAS G13C, and CypA

This is a non-PDB format compatible entry.

Summary for 36OI

• Entry DOI: 10.2210/pdb36oi/pdb
• Descriptor: Isoform 2B of GTPase KRas, Peptidyl-prolyl cis-trans isomerase A, PHOSPHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER, ... (6 entities in total)
• Functional Keywords: inhibitor, complex, small gtpase, cancer, tri-complex, signaling protein-inhibitor complex, signaling protein
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 4
• Total formula weight: 77962.26

Authors

Read, B.,Tomlinson, A.C.A.,Knox, J.E.,Yano, J.K. (deposition date: 2026-06-23, release date: 2026-07-01)

Primary citation

Seamon, K.J.,Zhuang, Y.,Yang, Y.C.,Chakraborty, S.,Cregg, J.,Tomlinson, A.C.A.,Gould, A.,Ahler, E.,Maldonato, B.J.,Spradlin, J.N.,Pota, K.,Weller, C.,Marquez, A.,Wang, Z.,Koltun, E.S.,Knox, J.E.,Gill, A.L.,Smith, J.A.M.,Singh, M.,Jiang, J.,Wildes, D.,Holderfield, M.
Selective Inhibition of KRASG13C Reveals an Increased Dependence on Wild-Type RAS Isoforms in Codon 13 RAS-Mutant Cancers.
Cancer Discov, 2026

PubMed Abstract: Covalent KRAS G12C inhibitors have changed the treatment landscape for NSCLC and CRC patients, but numerous RAS-mutant cancers lack approved targeted therapies. Here we describe RMC-8839, an oral RAS(ON) G13C-selective, covalent, tri-complex inhibitor that induced tumor regressions in selected KRAS G13C-mutant xenograft models. However, one-third of KRAS G13C-mutant human cancer cell lines in vitro showed incomplete RAS pathway suppression despite near-complete KRAS G13C engagement, suggesting a role for wild-type RAS(ON). We find that codon 13-mutant RAS differs from other KRAS mutations, exhibiting decreased stability, increased nucleotide exchange, and substantial intrinsic and GAP-stimulated GTP hydrolysis, which decreases oncogenicity. Furthermore, co-occurring RAS pathway mutations leading to increased wild-type RAS activation are enriched in codon 13 mutant tumors. Consistent with a role for wild-type RAS(ON) signaling, combination of RMC-8839 with a RAS(ON) multi-selective inhibitor resulted in deeper inhibition of KRAS G13C-mutant xenograft tumor growth than either inhibitor alone.

PubMed: 42329095
DOI: 10.1158/2159-8290.CD-25-0886

Experimental method

X-RAY DIFFRACTION (1.47 Å)