PDBsum entry 6b0v

Signaling protein

PDB id: 6b0v

Contents

Protein chains

167 a.a.

Ligands

C8G ×2

GDP ×2

Metals

_CA ×4

Waters ×435

PDB id:

6b0v

Name:

Signaling protein

Title:

Crystal structure of small molecule ars-107 covalently bound to k-ras g12c

Structure:

Gtpase kras. Chain: a, b. Fragment: unp residues 1-169. Synonym: k-ras 2,ki-ras,c-k-ras,c-ki-ras. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: kras, kras2, rask2. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.29Å R-factor: 0.184 R-free: 0.218

Authors:

R.Hansen,U.Peters,A.Babbar,Y.Chen,J.Feng,M.R.Janes,L.-S.Li,P.Ren, Y.Liu,P.P.Zarrinkar

Key ref:

R.Hansen et al. (2018). The reactivity-driven biochemical mechanism of covalent KRAS^G12C inhibitors. Nat Struct Mol Biol, 25, 454-462. PubMed id: 29760531 DOI: 10.1038/s41594-018-0061-5

Date:

15-Sep-17 Release date: 16-May-18

Protein chains

P01116  (RASK_HUMAN) -  GTPase KRas from Homo sapiens

Seq: 189 a.a.

Struc: 167 a.a.*

* PDB and UniProt seqs differ at 9 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.6.5.2 - small monomeric GTPase.
• Reaction: GTP + H2O = GDP + phosphate + H⁺

GTP + H2O = GDP (Bound ligand (Het Group name = GDP) corresponds exactly) + phosphate + H(+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1038/s41594-018-0061-5

Nat Struct Mol Biol 25:454-462 (2018)

PubMed id: 29760531

The reactivity-driven biochemical mechanism of covalent KRAS^G12C inhibitors.

R.Hansen, U.Peters, A.Babbar, Y.Chen, J.Feng, M.R.Janes, L.S.Li, P.Ren, Y.Liu, P.P.Zarrinkar.

ABSTRACT

Activating mutations in KRAS are among the most common tumor driver mutations. Until recently, KRAS had been considered undruggable with small molecules; the discovery of the covalent KRAS^G12C inhibitors ARS-853 and ARS-1620 has demonstrated that it is feasible to inhibit KRAS with high potency in cells and animals. Although the biological activity of these inhibitors has been described, the biochemical mechanism of how the compounds achieve potent inhibition remained incompletely understood. We now show that the activity of ARS-853 and ARS-1620 is primarily driven by KRAS-mediated catalysis of the chemical reaction with Cys12 in human KRAS^G12C, while the reversible binding affinity is weak, in the hundreds of micromolar or higher range. The mechanism resolves how an induced, shallow and dynamic pocket not expected to support high-affinity binding of small molecules can nevertheless be targeted with potent inhibitors and may be applicable to other targets conventionally considered undruggable.