Covalent drugs
23 articles
Fumarate-tagged TTK inhibitor turns into a monovalent degrader via RNF126
- Appending an electrophilic monomethyl fumarate handle to a TTK inhibitor gave a single-warhead degrader, with no E3 ligand attached.
- The lead compound drove TTK degradation and showed stronger antiproliferative activity than the parent inhibitor across several cancer cell lines.
- Mechanistic work points to the E3 ligase RNF126, which the compound stabilizes in complex with TTK, leading to ubiquitination and proteasomal turnover.
Monovalent degraders are attractive because you keep the molecular weight and permeability of a plain inhibitor. The catch is that a fumarate handle is a cysteine-reactive group, so I'd want proteome-wide reactivity data before believing RNF126 is the whole story. Still, if the handle transfers across kinase scaffolds, it's a cheap trick to try on any inhibitor series you already own.
Electrophile-first screen yields covalent aminothiazole inhibitors of the E2 enzyme UBE2D2
- An electrophile-first screen, combined with X-ray crystallography, found a covalent hit that engages two cysteines (C85 and C111) of UBE2D2.
- Structure-guided SAR on the amide and ester groups removed binding to C111 while improving engagement of C85.
- The optimized analog inhibited UBE2D2 activity in vitro and suppressed proliferation of A549 lung cancer cells.
E2s have long been written off as undruggable, so seeing a crystal-supported covalent series is a real step. The interesting design move is dialing out the second cysteine, which is exactly what you need before calling anything a probe. I'd now ask how it behaves across other UBE2D family members, since the active-site cysteine is conserved and selectivity will be the hard part.
Epoxysuccinamide warheads hit SARS-CoV-2 PLpro hard, but a hydrazide linker undermines them
- Covalent PLpro inhibitors were designed by combining an epoxysuccinamide warhead for Cys-111 with groove-binding features borrowed from non-covalent inhibitors.
- The compounds showed very high enzymatic potency and strongly reduced viral titres in cell culture.
- The flexible hydrazide linker was cleaved by hepatic carboxylesterases, and alternative linkers did not work, so the series is metabolically limited.
A potent warhead that dies in the liver is a familiar story, and here the culprit is the very linker the chemistry needs for Cys-111 reach. I'd still keep the epoxysuccinamide in the toolbox for the next coronavirus, but the linker would be the first thing I'd redesign.
Discovery of Epoxysuccinates as Potent Covalent Inhibitors of SARS-CoV-2 Papain-like Protease ↗
CHARMM-GUI adds a web module that automates covalent ligand docking
- CGUI-CLD is a new CHARMM-GUI module that automates ligand preparation, ligand modification and docking runs for covalent ligands, built on AutoDock4.
- A knowledge-based library covers 66 warheads and 8 amino acids, so the post-reaction ligand geometry no longer has to be built by hand.
- Results are presented through a browser interface.
Covalent docking is where my own campaigns stall: building the bonded adduct for each warhead is tedious, so I triage by intuition. A browser tool that handles it would let me rank a whole warhead set against a cysteine pocket in an afternoon. Docking scores won't capture reactivity, so I'd still pair this with kinetic data.
CHARMM-GUI Covalent Ligand Docker as a Web-Based Molecular Docking Platform for Covalent Ligands ↗
A covalent ligand at cereblon's cryptic Cys287 locks the E3 ligase open and blocks IMiD-driven degradation
- Cysteine-directed chemoproteomic screening found covalent ligands for Cys287, an allosteric pocket far from the thalidomide-binding site.
- Lead VVD-105917 broadly blocks degradation of neosubstrates driven by IMiDs and CELMoDs.
- Cryo-EM shows it traps cereblon in its open, inactive state, and ligand order matters. A previously reported ligand at the same site promotes closure instead, so the pocket is 'sign-switchable'.
Every CRBN drug so far sits in one orthosteric pocket, so a covalent handle that controls the open/closed switch is a genuinely new knob. A pan-inhibitor is an excellent tool to dissect degrader mechanisms and rescue off-target degradation. A site that can push either way also means a degrader-enhancing ligand might be hiding in the same pocket. This is a preprint, so wait for review.
Allosteric covalent inhibition of cereblon through cryptic cysteine targeting ↗
High-content screen of a covalent library finds new early mitotic inhibitors
- A cell-based high-content imaging screen was built to catch early mitotic spindle assembly defects.
- Run against a 3,520-compound cysteine-reactive library, it found a microtubule depolymerizer, a spindle-positioning disruptor and compounds that disturb spindle structure and chromosome alignment.
- Two hits caused mitotic arrest and reduced cancer cell viability (preprint; not yet peer reviewed).
Phenotypic screening with a covalent library is a sensible way to find chemotypes that target-based approaches would never pick. The weak point is deconvolution: until the cysteine targets are identified, a microtubule depolymerizer risks being one more tubulin binder. Worth tracking for the non-tubulin hits.
Identification of Cysteine-Reactive Early Mitotic Inhibitors ↗
HTS-derived covalent inhibitors hit active, GTP-bound KRAS G12C
- Approved KRAS G12C drugs mostly trap the inactive GDP state and face resistance; this series targets the active GTP-bound state instead.
- A keto-indolizine HTS hit with an aniline-derived acrylamide binds Cys12 in the switch-II pocket; crystallography shows the warhead engaging the γ-phosphate of a GTP analogue.
- Optimization gave compound 17, orally bioavailable in preclinical species, which prolongs disruption of KRAS–cRAF binding and ERK signalling and produced complete regression in a pancreatic cancer xenograft.
Using the γ-phosphate to position the warhead is neat: GTP-state selectivity comes from the nucleotide itself, not only the pocket. The comparison I'd want is against RAS(ON) tri-complex inhibitors, which need cyclophilin A while this doesn't. Acrylamide reactivity and proteome-wide cysteine selectivity also matter more here than for GDP-state binders.
Covalent fragments reach lysines in the SHP2 allosteric latch site
- Combines an electrophile-first covalent fragment screen with a ligand-first strategy to target lysines in the allosteric latch site of SHP2 phosphatase.
- Computational and experimental analyses support the binding mode, and the work yields what the authors call the first potent, cell-active allosteric covalent inhibitors at this site.
- It shows the latch site is covalently tractable, opening routes to new allosteric SHP2 chemotypes.
Lysine-directed covalent chemistry is far rarer than cysteine, so a workflow that actually delivers cell-active hits on a lysine is the takeaway, more than SHP2 itself. My caveat is reactivity versus stability: lysine electrophiles can be hydrolytically fragile or reversible, so I'd want proteome-wide selectivity data before calling anything a probe.
Fragment-Based Covalent Targeting of Lysines at the Allosteric Latch Site of SHP2 ↗
Cyclooctyne click triggers Cope elimination to unmask Michael acceptor warheads and release payloads
- Michael acceptors are masked with a hydroxylamine; a bioorthogonal reaction with a cyclooctyne triggers Cope elimination, regenerating the electrophile under mild conditions.
- The approach covers several warhead types, including unsaturated carbonyl, cyano, sulfonyl, phosphonate and maleimide, with tunable activation rates.
- Functionalized cyclooctynes can release an imaging or functional payload at the same time, giving a signal that reports activation.
- Applied to covalent inhibitors, it gave controlled activation in cells.
Could a masked warhead finally fix the off-target reactivity of acrylamide-class leads? Caging the Michael acceptor as a hydroxylamine and uncaging it by cyclooctyne click is a neat way to turn on covalency only where you dose the trigger. From the abstract alone I would want the rate constants, whether the hydroxylamine-bearing prodrug keeps target affinity, and how the cyclooctyne's size and lipophilicity compare with a conventional warhead.
Shutting down JNK signaling resensitizes KRAS G12D-resistant pancreatic cancer cells
- Pancreatic cancer cells that adapt to KRAS G12D inhibition can be pushed back toward sensitivity by suppressing the JNK pathway more completely.
- Selective covalent inhibitors of MAP2K4, MAP2K7, or both were used to probe how much JNK suppression is needed.
- Stronger JNK blockade disables the feedback loop that reactivates KRAS signaling in resistant cells.
- Inhibitor-sensitive cells gain no benefit, so the vulnerability is specific to the resistant state.
If this holds up, the interesting part is the logic: resistance to a KRAS G12D inhibitor runs through JNK feedback, so you hit the node that rewires the pathway, not KRAS again. Covalent engagement of MAP2K4 and MAP2K7 is a neat way to ask how deep the suppression must be, though kinase selectivity between the two will be the real SAR headache. Sparing sensitive cells is the encouraging bit; it's abstract-level so far.
Covalent Cyclitol Aziridines Deliver a Brain-Penetrant, Selective GBA2 Inhibitor
- GBA2 has lacked inhibitors that separate it from GBA1 and glucosylceramide synthase; the team built a focused library of electrophilic cyclitols (epoxides, cyclic sulfates, N-alkyl aziridines) from earlier β-D-arabinofuranose activity-based probes.
- Profiling against GBA1, GBA2, GBA3 and glucosylceramide synthase identified covalent inhibitors selective for GBA2.
- The lead is reported as the first brain-penetrant covalent inhibitor to selectively inactivate GBA2 in vivo.
Turning an activity-based-probe scaffold into an in vivo tool compound is a neat path, and selectivity over GBA1 and GCS is precisely what GBA2 biology has been missing. For anyone working on sphingolipid or lysosomal storage disorders this is a usable tool. My open question is the covalent off-target profile at in vivo exposure, since aziridines are not quiet electrophiles.
Azaphilone Probe Maps Reactive Lysines Across Live Bacterial Proteomes
- SCL-alkyne, a simplified azaphilone derived from the natural product sclerotiorin, was designed to profile lysine reactivity proteome-wide in bacteria.
- It was highly lysine-selective in vitro and in live E. coli; most engaged sites were lysines or protein N-termini, and only a small subset of reactive lysines sat in functional regions.
- Enrichment analysis pointed to bacterial chemotaxis as a major target pathway, which was then confirmed.
Covalent ligand discovery has been cysteine-centric, and lysine-directed scaffolds beyond sulfonyl fluorides and activated esters are scarce, so a natural-product-derived option is appealing. The observation that few reactive lysines are functional is a sober reminder that reactivity is cheap and function is not. As an E. coli preprint it is a starting point for covalent fragments, not a lead.
Free Energy Calculations Assess Covalent Inhibitor Binding to Cruzain and Cathepsin L
- Uses relative binding free energy (FEP-type alchemical) calculations to compare warhead-bearing covalent inhibitors across two related cysteine proteases.
- Cruzain, the key protease of Trypanosoma cruzi (Chagas disease), and human cathepsin L, its close homolog, are modeled in parallel.
- Comparison highlights selectivity for the parasitic target versus off-target reactivity with the human enzyme, guiding optimization.
FEP on a reactive warhead is still shakier than on reversible binders — parameterizing the covalent bond is where these methods quietly break. Still, cat L cross-reactivity has sunk more cruzain leads than weak potency ever did, so a validated ΔΔG ranking that flags off-target binders before synthesis is real triage value — worth having when neglected-disease budgets don't cover redundant chemistry.
Two-Step Route Expands Warhead Diversity in Covalent Genetically-Encoded Macrocycle Libraries
- A two-step route builds covalent genetically-encoded macrocycle libraries (cGELs): cysteines form the macrocycle via a diketone linchpin, then a separate Knorr-pyrazole step adds the electrophilic warhead.
- Separating cyclization (basic pH) from warhead installation (acidic pH) avoids the regioisomer mixtures that limited earlier one-pot chemical modification methods.
- This lets more diverse, reactive electrophiles be used safely, broadening covalent chemotypes accessible for selections against protein targets in DEL-style screens.
Regioisomer scrambling in one-pot warhead installation is exactly what kills confidence when you're deconvoluting covalent DEL hits — you can't tell if a signal is real or an artifact of a messy electrophile mixture. Decoupling cyclization from Knorr-pyrazole warhead chemistry means finally screening exotic, more reactive electrophiles beyond the usual acrylamide/chloroacetamide workhorses without second-guessing every hit's identity.
Brain-Penetrant Covalent BChE Inhibitor Shows Procognitive Effects in Alzheimer's Model
- Researchers used structure-guided design to develop a covalent small-molecule inhibitor of human butyrylcholinesterase (BChE), an enzyme increasingly implicated in Alzheimer's disease progression.
- The lead compound was engineered for blood-brain barrier penetration, a key hurdle for centrally acting cholinesterase inhibitors.
- In vivo testing showed procognitive efficacy, supporting covalent BChE inhibition as a potential treatment approach for Alzheimer's disease.
BChE rising while AChE falls late in disease is finally moving the field past AChE-centric dogma. A covalent warhead in a serine hydrolase family full of close paralogs (AChE, esterases) needs hard selectivity data, not just potency. What actually differentiates this from rivastigmine-class reversible inhibitors is CNS penetration — brain exposure they never solved well.
One-Handed Molecule Disarms the Cell-Death Trigger BAX
- Research highlight on a stereoselective, cysteine-reactive molecule that locks the pro-apoptotic protein BAX into an inactive shape, blocking programmed cell death.
- Optimization yielded a lead compound suitable for in vivo dosing that limited liver-cell death and preserved organ function in a mouse model of acute liver injury.
- It also protected stem-cell-derived motor neurons from healthy and ALS-patient donors, pointing to wider relevance in neurodegenerative disease.
This is the kind of binding-mode elegance you rarely see survive contact with an animal model — a stereoselective, cysteine-directed covalent lock on BAX's inactive conformation, in a target class that's almost entirely been reversible PPI chemistry. Holding up in both a liver-injury model and ALS-donor motor neurons argues for real engagement, not a lucky crosslinker; I'd still want the off-target cysteine panel.
Lysine-Targeted Covalent Fragments Open a New Allosteric Route to Inhibit SHP2
- Researchers built a combined screening pipeline pairing covalent fragment screening with a ligand-first design strategy to find chemical matter that reacts with lysine side chains rather than the more commonly targeted cysteines.
- The work focuses on the allosteric "latch" region of SHP2 phosphatase, a regulatory site distinct from the enzyme's catalytic pocket and from previously drugged allosteric tunnel sites.
- Computational modeling and experimental characterization were used together to guide fragment selection and to understand how covalent attachment at latch-site lysines affects the protein's conformational behavior.
- The approach yielded inhibitors described as the first potent, cell-active covalent compounds acting through this latch site, indicating the pocket can support functional, drug-like engagement rather than only structural characterization.
- The findings position lysine-directed covalent chemistry as a viable route for allosteric SHP2 modulation and provide a starting chemotype and site for further medicinal chemistry optimization.
Lysine-directed covalency is the real bet here, more than the new pocket itself: warhead chemistry and selectivity triage are far less mature than for cysteine acrylamides, so the first thing I'd pull up is proteome-wide lysine reactivity data before trusting the cell activity. The latch site itself is also genuinely new — it sits apart from where SHP099/TNO155-type allosteric inhibitors already bind, so this isn't retreading crowded IP. Getting cell-active hits straight out of fragment screening is a strong signal for this pocket's shape or a hyperreactive lysine — but fragment-to-lead on Lys chemistry means slower SAR cycles than we're used to with Cys warheads. Real value: a fresh chemotype and site for a target whose allosteric space was starting to feel exhausted.
Fragment-Based Covalent Targeting of Lysines at the Allosteric Latch Site of SHP2 ↗
Structural Survey Reveals How Kinase Inhibitors Engage Conserved Catalytic Residues
- More than 300 X-ray cocrystal structures spanning diverse kinase-inhibitor complexes were analyzed to catalog recurring non-covalent contact patterns.
- The study highlights a set of conserved Lys, Asp, and Glu residues near the ATP pocket, dubbed "Catalytic Cluster Residues" (CCRs), that support catalysis and frequently contact bound inhibitors.
- Across most inhibitor chemotypes, these polar residues form non-covalent interactions rather than covalent bonds, making them broadly relevant handles for ligand design.
- Side-chain orientation of the CCRs tracks with the kinase's active or inactive conformational state, linking binding geometry to structural dynamics.
- The authors argue this conformation-coupled behavior can guide rational, structure-based inhibitor design aimed at improving potency and tuning selectivity across the kinome.
"Catalytic Cluster Residues" is new branding for something most kinase chemists already lean on informally — the Lys-Glu ion pair, DFG-Asp contacts. The real value here is systematizing it: 300+ structures gives a statistical backbone for deciding when to actually chase these polar contacts instead of hinge binding or a back-pocket selectivity vector. If CCR geometry really tracks active/inactive state, that's a usable lever — bias type-I vs type-II engagement via salt bridges and H-bonds instead of reaching for a covalent warhead, attractive when cysteine liabilities or covalent reversibility are a concern. I'm skeptical the conformational-coupling claim generalizes cleanly across the kinome, though — 300 structures sounds like a lot until you split it by subfamily, and PDB deposition bias means scaffolds like EGFR, ABL, and CDKs are almost certainly overrepresented relative to understudied kinases.
A Structural Perspective on Non-covalent Targeting of Conserved Polar Residues in Protein Kinases ↗
ER-Targeted NIR Probe Enables High-Throughput Discovery of hCES2A Inhibitors
- PA-HDCI, a near-infrared fluorogenic probe built on the HDCI fluorophore scaffold, localizes to the endoplasmic reticulum and reports on human carboxylesterase 2A (hCES2A) activity in living cells and animals.
- The probe combines a large Stokes shift, high metabolic stability, and reliable ER targeting, enabling in situ, real-time imaging of hCES2A function across multiple biological systems.
- Using PA-HDCI in a high-throughput screening assay, the team identified compound A4, a highly potent covalent inhibitor of hCES2A.
- hCES2A is the intestinal enzyme that converts the chemotherapy drug irinotecan into its toxic active metabolite, driving irinotecan-induced intestinal toxicity (IIT).
- In tumor-bearing mouse models, A4 showed a favorable safety profile and reduced irinotecan-associated intestinal toxicity while therapeutic efficacy was maintained.
- Together, the work delivers both a new imaging tool and a validated drug-discovery platform for hCES2A-targeted therapeutics.
Solid probe engineering, not just a screening reagent: coaxing ER-selective localization and a large Stokes shift out of the HDCI scaffold gives clean signal separation in situ — photophysics that holds up in cells, not just a cuvette. The real value-add is methodological. A mechanistic imaging tool doubling as an HTS readout turns hCES2A activity into a screenable phenotype in living systems, closing the usual gap between biochemical assays and cellular reality. Target-wise, nothing novel here — hCES2A is a known off-target liability that bioactivates irinotecan into its gut-toxic metabolite, so this is a 'fix the side effect' play, not a new mechanism. A4 is an HTS-derived covalent hit with encouraging mouse data, but still needs the standard covalent-hit workup: reactivity profiling, esterase-family selectivity, and SAR.
Covalent Metal-Complex Platform Maps Proteome-Wide Cysteines, Nets a PRMT1 Inhibitor
- Introduces reactive metallo-scaffolds (r-mS), a new class of covalent metal complexes bearing a chloroacetamide electrophile designed to engage ligandable cysteines across the proteome.
- Chemoproteomic profiling of a focused r-mS series in HEK293T cell lysate mapped novel cysteine engagement proteome-wide.
- Metal identity, arene substituents, and overall scaffold topography together tune cysteine reactivity and targeting selectivity.
- Lead compound r-mS-2 engages a cysteine within the functionally relevant SAM-binding domain of the methyltransferase PRMT1, confirmed by intact-protein LC-MS.
- That engagement functionally inhibits PRMT1 activity, tying a covalent hit directly to modulation of a validated target.
- Positions the platform as a generalizable route to target discovery for rational, next-generation metallodrug design.
The SAM-pocket cysteine hit on PRMT1 is the part I trust most here — that's a genuinely druggable site, and confirming occupancy by intact-protein LC-MS rather than an activity readout alone is the right bar. Where I'd slow down is selectivity: tuning reactivity through metal identity and arene substituents is a real lever, but it's one more variable than iodoacetamide/chloroacetamide fragment libraries already juggle, and a lysate screen doesn't tell me the off-target cysteine load in cells. Chemically, this is genuinely unfamiliar ground for most of us — ligand exchange, redox lability, and batch-to-batch reproducibility are liabilities organic warheads simply don't have. Against established cysteine-directed chemoproteomic platforms, r-mS adds an interesting third tuning axis, not yet a clear win. Metallodrugs as a class still carry that same tractability tax relative to organic small molecules — worth watching, not yet worth reaching for.
Tideglusib Identified as First Chemical Probe for NatA Acetyltransferase via Novel Covalent Mechanism
- NatA catalyzes a large share of eukaryotic Nα-acetylation, a co-translational modification important for protein stability, localization and function; no validated small-molecule NatA probe had previously been reported.
- Screening an in-house ~700-compound library and optimizing a thiadiazolidinedione scaffold identified tideglusib (YD3139) — a clinical-stage GSK-3β inhibitor — as a hit, repurposing a known drug toward NatA.
- Mechanistic studies showed tideglusib first binds NatA allosterically, after which CoA released during catalysis chemically modifies it into a reversible covalent adduct, a previously undescribed catalysis-dependent inhibition mechanism.
- The compound showed low-micromolar potency against yeast and human NatA with good selectivity over other NAT family members, and proteomics confirmed on-target activity in yeast cells, validating it as a mechanistic chemical probe.
What earns this a second look is the mechanism: an allosteric binder that stays non-covalent until the enzyme's own turnover releases CoA to staple it in place — a genuinely new trick, not just another warhead. Whether it generalizes beyond NatA's odd CoA-release chemistry is unclear, but it's worth filing away as a template for other CoA- or cofactor-dependent enzymes. The selectivity over other NATs despite a conserved active site is the more actionable lesson: skip the catalytic pocket, go allosteric, and you dodge the conservation problem for free. As probe discovery, repurposing tideglusib beats de novo synthesis for speed, but it also means every existing GSK-3β dataset on this molecule is now confounded — nobody should read across to NatA biology from tideglusib phenotypes without new chemical matter. NatA itself looks like a legitimate, underexplored target; this is a probe paper, not a drug paper, but it's the right first step.
Covalent Molecular Glue Locks Kalirin-Rac1 Complex to Halt GTPase Activation
- Researchers combined XChem crystallographic fragment screening with in silico screening, then merged fragment hits into covalent leads targeting the Kalirin-Rac1 GEF-GTPase complex.
- Instead of directly competing with GTP/GDP for Rac1's binding site, the covalent compounds act as molecular glues, locking Kalirin and Rac1 into an inactive ternary complex that blocks nucleotide exchange.
- Two resulting inhibitors, RS-009 and MC-278, reduce Kalirin's GEF activity through this dual action: partial nucleotide competition plus stabilization of the non-productive complex.
- Biochemical selectivity panels and cellular activity-based protein profiling show the compounds can distinguish among different GEF-GTPase pairs rather than acting indiscriminately.
- The authors frame this as an alternative to direct GTPase inhibition that could offer finer spatiotemporal control, positioning RS-009/MC-278 as chemical probe candidates.
Locking down the non-productive Kalirin-Rac1 complex rather than competing head-on for the nucleotide pocket is the smarter play — GTP/GDP affinity is sub-nanomolar, and pan-Rac1 nucleotide-pocket tools like NSC23766 have never been clean. It's the SOS1-KRAS playbook applied to Rho biology, not a new idea, but a good one to borrow. Selectivity across GEF-GTPase pairs is the actual prize, not a burden — Rho-family homology is brutal, so an interface-driven selectivity handle beats trying to differentiate active-site chemistry. What I'd interrogate: fragment merging from XChem hits into covalent leads has a high attrition rate, so two validated compounds (RS-009, MC-278) is a real result, not a given. Before calling these clean probes I want warhead kinetics and full-proteome ABPP, not just the GEF-GTPase panel.
Discovery of a molecular glue inhibitor that stabilises a non-productive Kalirin-Rac1 complex ↗
Covalent Small Molecule RVJB59 Stabilizes Two Cancer-Driving p53 Mutants
- p53 is the tumor suppressor most frequently inactivated in cancer, and hotspot mutations such as R280K and R273H destabilize the folded DNA-binding domain, making mutant p53 reactivation a long-standing 'undruggable' target class.
- The study describes RVJB59, a small molecule from a tryptophanol-derived oxazoloisoindolinone series, designed to covalently engage mutant p53 protein rather than bind it only reversibly.
- Biophysical thermal-stability assays reported for this compound series show increased melting stability of mutant p53 DNA-binding domains, consistent with partial restoration of a more folded, wild-type-like conformation.
- Combining covalent engagement with thermostabilization supports a mutant-reactivation strategy aimed at restoring p53 tumor-suppressor function in cancers driven by the R280K and R273H mutations.
Mutant p53 reactivation is the target class every oncology med chemist wants a win on — most p53 lesions are destabilizing loss-of-function, not a clean druggable pocket, so 'fix the fold' beats 'block the site.' RVJB59's angle — covalent engagement plus measurable thermal stabilization of R280K and R273H DBDs — is mechanistically the right read: lock a reactive residue, nudge the folding equilibrium back toward a wild-type-like conformation. My first questions are the covalent-chemist ones: which residue, what warhead, how clean is selectivity across the proteome — thermal-shift data alone won't settle that. Worth benchmarking against PC14586/rezatapopt's reversible pocket-binding approach for R175H; different mutant, different chemotype, same underlying bet. Reads as solid hit-to-lead chemical biology, not anything near clinic-ready.