39AS
Crystal structure of LUCI-tag, bound to adagrasib
Summary for 39AS
| Entry DOI | 10.2210/pdb39as/pdb |
| Descriptor | LUCI-tag, {(2S)-4-[7-(8-chloronaphthalen-1-yl)-2-{[(2S)-1-methylpyrrolidin-2-yl]methoxy}-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidin-4-yl]-1-[(2S)-2-fluoropropanoyl]piperazin-2-yl}acetonitrile, GUANOSINE-5'-DIPHOSPHATE, ... (5 entities in total) |
| Functional Keywords | k-ras(g12c), sequence redesign, gtpase, self-labeling protein, de novo protein |
| Biological source | synthetic construct |
| Total number of polymer chains | 4 |
| Total formula weight | 78947.44 |
| Authors | |
| Primary citation | Mou, J.,Leong, J.W.,Gao, S.,Slaw, K.,McGill, M.,Donovan, K.A.,Metivier, R.J.,Sendker, F.L.,Kong, Q.,Lin, D.,Dharani, A.M.,Chen, X.D.,Haigis, K.M.,Fischer, E.S.,Chen, F.,Polizzi, N.F. Deep-learning-based design of an orthogonal self-labeling protein from K-Ras(G12C). Biorxiv, 2026 Cited by PubMed Abstract: Self-labeling protein (SLP) tags enable versatile labeling of proteins in live cells, yet only two SLPs are commonly used, limiting multiplexing. Here, we repurposed the oncoprotein K-Ras(G12C) and its covalent inhibitors to create a third, orthogonal SLP system. We used a deep-learning-based approach to radically redesign the sequence of K-Ras(G12C) while preserving its covalent-inhibitor binding pocket. Our top design, LUCI-tag, is a 19 kDa, monomeric, thermostable SLP that rapidly and covalently reacts with commercially available K-Ras(G12C) inhibitors bearing diverse payloads. Unlike existing SLPs, LUCI-tag exhibited payload-agnostic labeling kinetics, outperforming HaloTag7 and SNAP-tag for a negatively charged payload. X-ray crystal structures of drug-bound and drug-free LUCI-tag showed the design was structurally accurate and contained a preorganized inhibitor-binding pocket that could explain its rapid labeling kinetics. Proteomics and cell-signaling experiments confirmed LUCI-tag is biologically inert. LUCI-tag enabled rapid, wash-free, live-cell imaging and simultaneous three-color multiplexed experiments with HaloTag7 and SNAP-tag. This work establishes LUCI-tag as an immediately useful orthogonal SLP and demonstrates that covalent drug-target pairs can be repurposed into a broadly applicable platform for protein labeling. PubMed: 42856208DOI: 10.64898/2026.09.27.754867 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.94 Å) |
Structure validation
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