4OBE

Crystal Structure of GDP-bound Human KRas

Summary for 4OBE

• Entry DOI: 10.2210/pdb4obe/pdb
• Related: 4LDJ 4NMM
• Descriptor: GTPase KRas, GUANOSINE-5'-DIPHOSPHATE, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: small gtpase, signal transduction, gdp binding, gtp binding, hydrolase
• Biological source: Homo sapiens (human)
• Cellular location: Cell membrane; Lipid-anchor; Cytoplasmic side: P01116
• Total number of polymer chains: 2
• Total formula weight: 39592.63

Authors

Hunter, J.C.,Gurbani, D.,Chen, Z.,Westover, K.D. (deposition date: 2014-01-07, release date: 2014-06-04, Last modification date: 2023-09-20)

Primary citation

Hunter, J.C.,Gurbani, D.,Ficarro, S.B.,Carrasco, M.A.,Lim, S.M.,Choi, H.G.,Xie, T.,Marto, J.A.,Chen, Z.,Gray, N.S.,Westover, K.D.
In situ selectivity profiling and crystal structure of SML-8-73-1, an active site inhibitor of oncogenic K-Ras G12C.
Proc.Natl.Acad.Sci.USA, 111:8895-8900, 2014

PubMed Abstract: Directly targeting oncogenic V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (K-Ras) with small-molecule inhibitors has historically been considered prohibitively challenging. Recent reports of compounds that bind directly to the K-Ras G12C mutant suggest avenues to overcome key obstacles that stand in the way of developing such compounds. We aim to target the guanine nucleotide (GN)-binding pocket because the natural contents of this pocket dictate the signaling state of K-Ras. Here, we characterize the irreversible inhibitor SML-8-73-1 (SML), which targets the GN-binding pocket of K-Ras G12C. We report a high-resolution X-ray crystal structure of G12C K-Ras bound to SML, revealing that the compound binds in a manner similar to GDP, forming a covalent linkage with Cys-12. The resulting conformation renders K-Ras in the open, inactive conformation, which is not predicted to associate productively with or activate downstream effectors. Conservation analysis of the Ras family GN-binding pocket reveals variability in the side chains surrounding the active site and adjacent regions, especially in the switch I region. This variability may enable building specificity into new iterations of Ras and other GTPase inhibitors. High-resolution in situ chemical proteomic profiling of SML confirms that SML effectively discriminates between K-Ras G12C and other cellular GTP-binding proteins. A biochemical assay provides additional evidence that SML is able to compete with millimolar concentrations of GTP and GDP for the GN-binding site.

PubMed: 24889603
DOI: 10.1073/pnas.1404639111

Experimental method

X-RAY DIFFRACTION (1.24 Å)