Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 3 de 3
Filter
Add more filters










Database
Language
Publication year range
1.
ACS Infect Dis ; 2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38873918

ABSTRACT

Shiga toxins are the main virulence factors of Shiga toxin producing E. coli (STEC) and S. dysenteriae. There is no effective therapy to counter the disease caused by these toxins. The A1 subunits of Shiga toxins bind the C-termini of ribosomal P-stalk proteins to depurinate the sarcin/ricin loop. The ribosome binding site of Shiga toxin 2 has not been targeted by small molecules. We screened a fragment library against the A1 subunit of Shiga toxin 2 (Stx2A1) and identified a fragment, BTB13086, which bound at the ribosome binding site and mimicked the binding mode of the P-stalk proteins. We synthesized analogs of BTB13086 and identified a series of molecules with similar affinity and inhibitory activity. These are the first compounds that bind at the ribosome binding site of Stx2A1 and inhibit activity. These compounds hold great promise for further inhibitor development against STEC infection.

2.
Bioorg Med Chem ; 100: 117614, 2024 Feb 15.
Article in English | MEDLINE | ID: mdl-38340640

ABSTRACT

Ricin, a category-B agent for bioterrorism, and Shiga toxins (Stxs), which cause food poisoning bind to the ribosomal P-stalk to depurinate the sarcin/ricin loop. No effective therapy exists for ricin or Stx intoxication. Ribosome binding sites of the toxins have not been targeted by small molecules. We previously identified CC10501, which inhibits toxin activity by binding the P-stalk pocket of ricin toxin A subunit (RTA) remote from the catalytic site. Here, we developed a fluorescence polarization assay and identified a new class of compounds, which bind P-stalk pocket of RTA with higher affinity and inhibit catalytic activity with submicromolar potency. A lead compound, RU-NT-206, bound P-stalk pocket of RTA with similar affinity as a five-fold larger P-stalk peptide and protected cells against ricin and Stx2 holotoxins for the first time. These results validate the P-stalk binding site of RTA as a critical target for allosteric inhibition of the active site.


Subject(s)
Ricin , Binding Sites , Peptides/pharmacology , Protein Binding , Ribosomes/metabolism , Ricin/antagonists & inhibitors , Ricin/metabolism
3.
J Med Chem ; 64(20): 15334-15348, 2021 10 28.
Article in English | MEDLINE | ID: mdl-34648707

ABSTRACT

Ricin toxin A subunit (RTA) is the catalytic subunit of ricin, which depurinates an adenine from the sarcin/ricin loop in eukaryotic ribosomes. There are no approved inhibitors against ricin. We used a new strategy to disrupt RTA-ribosome interactions by fragment screening using surface plasmon resonance. Here, using a structure-guided approach, we improved the affinity and inhibitory activity of small-molecular-weight lead compounds and obtained improved compounds with over an order of magnitude higher efficiency. Four advanced compounds were characterized by X-ray crystallography. They bind at the RTA-ribosome binding site as the original compound but in a distinctive manner. These inhibitors bind remotely from the catalytic site and cause local conformational changes with no alteration of the catalytic site geometry. Yet they inhibit depurination by ricin holotoxin and inhibit the cytotoxicity of ricin in mammalian cells. They are the first agents that protect against ricin holotoxin by acting directly on RTA.


Subject(s)
Drug Design , Enzyme Inhibitors/pharmacology , Ribosomes/drug effects , Ricin/antagonists & inhibitors , Small Molecule Libraries/pharmacology , Animals , Binding Sites/drug effects , Chlorocebus aethiops , Crystallography, X-Ray , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Models, Molecular , Molecular Structure , Ricin/metabolism , Small Molecule Libraries/chemical synthesis , Small Molecule Libraries/chemistry , Structure-Activity Relationship , Surface Plasmon Resonance , Vero Cells
SELECTION OF CITATIONS
SEARCH DETAIL
...