Functional AdoMet Isosteres Resistant to Classical AdoMet Degradation Pathways

Area of Science:

• Biochemistry
• Enzymology
• Medicinal Chemistry

Background:

• S-adenosyl-l-methionine (AdoMet) is a crucial enzyme cosubstrate in biological methylation reactions.
• AdoMet is susceptible to degradation via depurination, cyclization, and epimerization, limiting its therapeutic and biocatalytic utility.
• Developing stable AdoMet analogs is essential for expanding its applications.

Purpose of the Study:

• To design, synthesize, and evaluate novel, stable S-adenosyl-l-methionine (AdoMet) isosteres.
• To assess the functional competence and binding characteristics of these AdoMet surrogates with methyltransferases.
• To explore the potential of these isosteres as therapeutic agents and in novel assay development.

Main Methods:

• Chemical synthesis of novel AdoMet isosteres.
• Biochemical assays to evaluate enzyme cosubstrate activity.
• Structural studies using X-ray crystallography to determine binding modes.
• Enzyme inhibition assays targeting AdoMet-dependent enzymes.

Main Results:

• Stable AdoMet isosteres were successfully synthesized and demonstrated resistance to key degradation pathways.
• These isosteres function as competent enzyme cosubstrates, comparable to native AdoMet.
• Structural analysis revealed near-identical binding of isosteres to the methyltransferase DnrK compared to AdoMet.
• The methyltransferase DnrK demonstrated acceptance of non-native surrogate acceptors, enabling new assay development.

Conclusions:

• The developed AdoMet isosteres are stable, functional cosubstrates with potential for various AdoMet-dependent processes.
• These surrogates may offer resistance to or inhibit therapeutically relevant metabolic transformations.
• The ability of DnrK to accept non-native acceptors facilitates the development of high-throughput methyltransferase assays.