Biology subjects

Peacock, D. M.

Publications and source records attributed to Peacock, D. M..

2 recordsLinked to original sources

bioRxiv2022

Probing the KRas Switch II Groove by Fluorine NMR Spectroscopy

While there has been recent success in the development of KRasG12C inhibitors, unmet needs for selective inhibitors and tool compounds targeting the remaining oncogenic KRas proteins remain. Here, we applied trifluoromethyl-containing ligands of KRas proteins as competitive probe ligands to assay the occupancy of the switch II pocket by 19F NMR spectroscopy. Structure-activity-relationship studies of probe ligands increased the sensitivity of the assay and identified structures that differentially detected each nucleotide state of KRasG12D. These differences in selectivity, combined with the high resolution of 19F NMR spectroscopy, enabled this method to be expanded to assay both nucleotide states of the protein simultaneously. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/500267v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@2fe99corg.highwire.dtl.DTLVardef@19223bdorg.highwire.dtl.DTLVardef@1686090org.highwire.dtl.DTLVardef@19b9d05_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2021

KRAS is vulnerable to reversible switch-II pocket engagement in cells

Current small molecule inhibitors of KRAS(G12C) bind irreversibly in the switch-II pocket, exploiting the strong nucleophilicity of the acquired cysteine as well as the preponderance of the GDP-bound form of this mutant. Nevertheless, many oncogenic KRAS mutants lack these two features, and it remains unknown whether targeting the switch-II pocket is a practical therapeutic approach for KRAS mutants beyond G12C. Here we use NMR spectroscopy and a novel cellular KRAS engagement assay to address this question by examining a collection of SII-P ligands from the literature and from our own laboratory. We show that the switch-II pockets of many GTP hydrolysis-deficient KRAS hotspot (G12, G13, Q61) mutants are accessible using non-covalent ligands, and that this accessibility is not necessarily coupled to the GDP state of KRAS. The results we describe here emphasize the switch-II pocket as a privileged drug binding site on KRAS and unveil new therapeutic opportunities in RAS-driven cancer.

cancer biology↗