Synthesis, Biochemical Characterization, and Genetic Encoding of a 1,2,4‐Triazole Amino Acid as an Acetyllysine Mimic for Bromodomains of the BET Family

• Published in: Angewandte Chemie International Edition Vol. 62; no. 12; pp. e202215460 - n/a
• Main Authors: Kirchgäßner, Sören, Braun, Michael B., Bartlick, Natascha, Koç, Cengiz, Reinkemeier, Christopher D., Lemke, Edward A., Stehle, Thilo, Schwarzer, Dirk
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 13.03.2023
• Edition: International ed. in English
• Subjects: Acetylation; Acetyllysine; Amino Acids; Bromodomain; Chemical Biology; Genetic code; Genetic Code Expansion; Glutamine; In vivo methods and tests; Lysates; Lysine; Lysine Acetylation; Neutralization; Optimization; Peptides; Peptides - chemistry; Protein Domains; Protein Modification; Proteins; Recruitment; Substrates; Triazoles; Chemical Biology; Protein Modification; Genetic Code Expansion; Bromodomain; Lysine Acetylation
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202215460

Lysine acetylation is a charge‐neutralizing post‐translational modification of proteins bound by bromodomains (Brds). A 1,2,4‐triazole amino acid (ApmTri) was established as acetyllysine (Kac) mimic recruiting Brds of the BET family in contrast to glutamine commonly used for simulating this modification. Optimization of triazole substituents and side chain spacing allowed BET Brd recruitment to ApmTri‐containing peptides with affinities similar to native substrates. Crystal structures of ApmTri‐containing peptides in complex with two BET Brds revealed the binding mode which mirrored that of Kac ligands. ApmTri was genetically encoded and recombinant ApmTri‐containing proteins co‐enriched BRD3(2) from cellular lysates. This interaction was blocked by BET inhibitor JQ1. With genetically encoded ApmTri, biochemistry is now provided with a stable Kac mimic reflecting charge neutralization and Brd recruitment, allowing new investigations into BET proteins in vitro and in vivo. A triazole‐containing amino acid (ApmTri) was established as a mimic of acetyllysine for bromodomains of the BET family. Biochemical and structural investigations showed that ApmTri binds with similar affinity to bromodomains as acetyllysine and reflects the binding mode of the native modification at the atomic level. Genetic encoding enables ApmTri incorporation into proteins allowing investigations of bromodomain binding properties and inhibition.