Redirecting raltitrexed from cancer cell thymidylate synthase to Mycobacterium tuberculosis phosphopantetheinyl transferase.

TitleRedirecting raltitrexed from cancer cell thymidylate synthase to Mycobacterium tuberculosis phosphopantetheinyl transferase.
Publication TypeJournal Article
Year of Publication2024
AuthorsSingh A, Ottavi S, Krieger I, Planck K, Perkowski A, Kaneko T, Davis AM, Suh C, Zhang D, Goullieux L, Alex A, Roubert C, Gardner M, Preston M, Smith DM, Ling Y, Roberts J, Cautain B, Upton A, Cooper CB, Serbina N, Tanvir Z, Mosior J, Ouerfelli O, Yang G, Gold BS, Rhee KY, Sacchettini JC, Fotouhi N, Aubé J, Nathan C
JournalSci Adv
Volume10
Issue11
Paginationeadj6406
Date Published2024 Mar 15
ISSN2375-2548
KeywordsBacterial Proteins, Humans, Mycobacterium tuberculosis, Neoplasms, Quinazolines, Thiophenes, Thymidylate Synthase, Transferases (Other Substituted Phosphate Groups)
Abstract

There is a compelling need to find drugs active against Mycobacterium tuberculosis (Mtb). 4'-Phosphopantetheinyl transferase (PptT) is an essential enzyme in Mtb that has attracted interest as a potential drug target. We optimized a PptT assay, used it to screen 422,740 compounds, and identified raltitrexed, an antineoplastic antimetabolite, as the most potent PptT inhibitor yet reported. While trying unsuccessfully to improve raltitrexed's ability to kill Mtb and remove its ability to kill human cells, we learned three lessons that may help others developing antibiotics. First, binding of raltitrexed substantially changed the configuration of the PptT active site, complicating molecular modeling of analogs based on the unliganded crystal structure or the structure of cocrystals with inhibitors of another class. Second, minor changes in the raltitrexed molecule changed its target in Mtb from PptT to dihydrofolate reductase (DHFR). Third, the structure-activity relationship for over 800 raltitrexed analogs only became interpretable when we quantified and characterized the compounds' intrabacterial accumulation and transformation.

DOI10.1126/sciadv.adj6406
Alternate JournalSci Adv
PubMed ID38489355
PubMed Central IDPMC10942122
Grant ListP30 CA008748 / CA / NCI NIH HHS / United States
R01 AI155510 / AI / NIAID NIH HHS / United States

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