Related Experiment Video

Updated: Aug 6, 2026

Covalent Fragment Screening Using the Quantitative Irreversible Tethering Assay
06:17

Covalent Fragment Screening Using the Quantitative Irreversible Tethering Assay

Published on: February 28, 2025

Stereoselective Covalent Targeting of BTK(C481S) and Kinases with β-Lactone Electrophiles

Celine D Wang1,2, Polina E Barzova1, Julian Robles1

  • 1Department of Chemistry, University of California, Berkeley, California 94720, USA.

Biorxiv : the Preprint Server for Biology
|July 17, 2026
PubMed

Insights

Researchers developed novel chiral β-lactone molecules to overcome resistance to ibrutinib, a drug used for certain leukemias and lymphomas. These molecules selectively target Bruton

Area of Science:

  • Medicinal Chemistry
  • Chemical Biology
  • Oncology

Background:

  • Bruton's tyrosine kinase (BTK) is a key target in treating B-cell malignancies.
  • Cysteine 481 (C481) mutations in BTK confer clinical resistance to ibrutinib.
  • Developing strategies to overcome ibrutinib resistance is crucial for effective cancer therapy.

Purpose of the Study:

  • To design and synthesize novel small molecule ligands targeting resistant BTK mutations.
  • To explore the potential of chiral β-lactone electrophiles as covalent warheads for selective kinase inhibition.
  • To investigate the stereochemical control of covalent modification for drug discovery.

Main Methods:

  • Synthesis of chiral β-lactone electrophiles.
  • Biochemical assays to assess covalent modification of wild-type and mutant BTK.
  • Development of kinase-directed probes for kinome profiling.
  • Stereoselective synthesis and evaluation of individual enantiomers.

Main Results:

  • Chiral β-lactones achieved stereoselective covalent modification of both wild-type and BTK(C481S) mutant.
  • Distinct sites of reactivity were observed for different enantiomers.
  • Kinase-directed probes revealed enantiomer-specific engagement of kinome subsets.
  • β-lactones function as stereochemically encodable covalent warheads.

Conclusions:

  • Chiral β-lactones represent a promising strategy to overcome ibrutinib resistance in BTK-related cancers.
  • The stereochemistry of β-lactones can be utilized as a selectivity filter in covalent drug design.
  • This work expands the toolbox for developing targeted covalent inhibitors with improved selectivity and efficacy.

More Related Videos

Identification of Novel CK2 Kinase Substrates Using a Versatile Biochemical Approach11:11

Identification of Novel CK2 Kinase Substrates Using a Versatile Biochemical Approach

Published on: February 21, 2019

High-Throughput Cellular Profiling of Targeted Protein Degradation Compounds Using HiBiT CRISPR Cell Lines05:33

High-Throughput Cellular Profiling of Targeted Protein Degradation Compounds Using HiBiT CRISPR Cell Lines

Published on: November 9, 2020

Related Concept Videos

α-Alkylation of Ketones via Enolate Ions01:10

α-Alkylation of Ketones via Enolate Ions

Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by resonance, and its hybrid structure exhibits negative charges on the carbonyl oxygen and the α carbon. This ambident nucleophile can attack an electrophile via two possible sites: the carbonyl oxygen, known as O-attack, or the α carbon, known as C-attack. The nucleophilic attack via the carbanionic site is preferred. This is due to the strong interaction...
Targeted Cancer Therapies02:57

Targeted Cancer Therapies

The targeted cancer therapies, also known as “molecular targeted therapies,” take advantage of the molecular and genetic differences between the cancer cells and the normal cells. It needs a thorough understanding of the cancer cells to develop drugs that can target specific molecular aspects that drive the growth, progression, and spread of cancer cells without affecting the growth and survival of other normal cells in the body.
There are several types of targeted therapies against specific...
Regioselectivity and Stereochemistry of Hydroboration02:36

Regioselectivity and Stereochemistry of Hydroboration

A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
SN2 Reaction: Stereochemistry02:23

SN2 Reaction: Stereochemistry

In an SN2 reaction, the nucleophilic attack on the substrate and departure of the leaving group occurs simultaneously through a transition state. As the nucleophile approaches the substrate from the back-side, the configuration of the substrate carbon changes from tetrahedral to trigonal bipyramidal and then back to tetrahedral, leading to an inversion in the configuration of the product.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.
Transducer Mechanism: Enzyme-Linked Receptors01:27

Transducer Mechanism: Enzyme-Linked Receptors

Enzyme-linked receptors are cell-surface receptors acting as an enzyme or associating with an enzyme intracellularly. They make excellent drug targets. Drugs can bind to the extracellular ligand-binding domain or directly affect their enzymatic domain and alter their activity.
Major types that are helpful drug targets include:
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis01:07

Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis

Acetoacetic ester synthesis is a method to obtain ketones from alkyl halides and β-keto esters. The reaction occurs in the presence of an alkoxide base that abstracts the acidic proton of the β-keto esters. The step results in an enolate ion which is doubly stabilized. The enolate then reacts with an alkyl halide via the SN2 process to produce an alkylated ester intermediate with a new C–C bond. The hydrolysis of the intermediate, followed by acidification, results in an alkylated β-keto acid.