PDBsum entry 5ufe

Hydrolase/de novo protein

PDB id: 5ufe

Contents

Protein chains

166 a.a.

54 a.a.

Ligands

GNP

Metals

_CO ×3

_CA ×3

_CD ×4

_CL ×3

_MG

Waters ×95

References listed in PDB file

Key reference

• Title: An engineered protein antagonist of k-Ras/b-Raf interaction.
• Authors: M.J.Kauke, M.W.Traxlmayr, J.A.Parker, J.D.Kiefer, R.Knihtila, J.Mcgee, G.Verdine, C.Mattos, K.D.Wittrup.
• Ref.: Sci Rep, 2017, 7, 5831.
• PubMed id: 28724936

Abstract

Ras is at the hub of signal transduction pathways controlling cell proliferation and survival. Its mutants, present in about 30% of human cancers, are major drivers of oncogenesis and render tumors unresponsive to standard therapies. Here we report the engineering of a protein scaffold for preferential binding to K-Ras G12D. This is the first reported inhibitor to achieve nanomolar affinity while exhibiting specificity for mutant over wild type (WT) K-Ras. Crystal structures of the protein R11.1.6 in complex with K-Ras WT and K-Ras G12D offer insight into the structural basis for specificity, highlighting differences in the switch I conformation as the major defining element in the higher affinity interaction. R11.1.6 directly blocks interaction with Raf and reduces signaling through the Raf/MEK/ERK pathway. Our results support greater consideration of the state of switch I and provide a novel tool to study Ras biology. Most importantly, this work makes an unprecedented contribution to Ras research in inhibitor development strategy by revealing details of a targetable binding surface. Unlike the polar interfaces found for Ras/effector interactions, the K-Ras/R11.1.6 complex reveals an extensive hydrophobic interface that can serve as a template to advance the development of high affinity, non-covalent inhibitors of K-Ras oncogenic mutants.