Marcos Pires, Ph.D. '03 will be Chemistry Departments seminar guest speaker Tuesday, November 4th at 4:15 p.m. in CNS 333. The title of the presentation is: “Unnatural D-Amino Acids as Novel Antibiotic Agents and Diagnostic Tools”Marcos Pires, Ph.D. '03 will be Chemistry Departments seminar guest speaker Tuesday, November 4th at 4:15 p.m. in CNS 333. The title of the presentation is: “Unnatural D-Amino Acids as Novel Antibiotic Agents and Diagnostic Tools”
Alarming incidences of drug-resistant bacterial infections have resulted in an urgent need for new antibiotics. During the past three decades, traditional drug discovery efforts have failed to yield a sufficient number of drugs with new mechanisms of action. More recently, non-traditional methods and the re-potentiation of validated targets have emerged as powerful strategies to complement these efforts. We, as well as others, have recently demonstrated that transpeptidases (enzymes responsible for crosslinking cell wall peptidoglycan stem peptides) also catalyze the replacement of surface-bound D-alanine with unnatural D-amino acids from the surrounding medium. We have also observed that these enzymes display extreme promiscuity in the recognition of the D-amino acid side chain and C-terminus. The relaxed selectivity of the substrate side chain can be exploited to modify bacterial cell surfaces by direct metabolic incorporation. Facile labeling is possible with the addition of exogenously supplied unnatural D-amino acids equipped with tailor-made handles. During the seminar, I will detail our recent work in the area of synthetic immunology to generate a class of compounds that engage components of the immune system in the clearance of pathogenic bacteria. We recently developed D-amino acid derivatives that selectively modify the surface of bacteria cells with small molecule antigens. The covalent surface tagging with the antigen dinitrophenyl results in an induction of phagocytosis by macrophages. I will also talk about how we have used D-amino acid variants to establish a rapid and reliable diagnostic test to identify bacteria and assess their drug-resistance levels using this same platform.
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https://www.ithaca.edu/intercom/article.php/2014102310435293