title: In Silico Discovery and Validation of Amide Based Small Molecule Targeting the Enzymatic Site of Shiga Toxin.
abstract: Shiga toxin (Stx), a category B biothreat agent, is a ribosome inactivating protein and toxic to human and animals. Here, we designed and synthesized small molecules that block the active site of the Stx A subunit. On the basis of binding energy, 20 molecules were selected for synthesis and evaluation. These molecules were primarily screened using fluorescence-based thermal shift assay and in vitro in Vero cells. Among 32 molecules (including 12 reported), six molecules offered protection with IC50of 2.60-23.90 μM. 4-Nitro-N-[2-(2-phenylsulfanylethylamino)ethyl]benzamide hydrochloride is the most potent inhibitor with IC50at 7.96 μM and selectivity index of 22.23 and is better than any known small molecule inhibitor of Stx. Preincubation with Stx offered full protection against Shiga toxin in mice. Surface plasmon resonance assay further confirmed that these molecules bind specifically to Stx A subunit. Further optimization is continued to identify a potential candidate which will be in vivo effective.
authors.affiliation: Biotechnology Division, ‡Synthetic Chemistry Division, and §Pharmacology and Toxicology Division, Defence Research and Development Establishment , Gwalior 474002, India.
authors.forename: Vinita
authors.initials: V
authors.lastname: Chauhan
authors.affiliation: Biotechnology Division, ‡Synthetic Chemistry Division, and §Pharmacology and Toxicology Division, Defence Research and Development Establishment , Gwalior 474002, India.
authors.forename: Dilip
authors.initials: D
authors.lastname: Chaudhary
authors.affiliation: Biotechnology Division, ‡Synthetic Chemistry Division, and §Pharmacology and Toxicology Division, Defence Research and Development Establishment , Gwalior 474002, India.
authors.forename: Uma
authors.initials: U
authors.lastname: Pathak
authors.affiliation: Biotechnology Division, ‡Synthetic Chemistry Division, and §Pharmacology and Toxicology Division, Defence Research and Development Establishment , Gwalior 474002, India.
authors.forename: Nandita
authors.initials: N
authors.lastname: Saxena
authors.affiliation: Biotechnology Division, ‡Synthetic Chemistry Division, and §Pharmacology and Toxicology Division, Defence Research and Development Establishment , Gwalior 474002, India.
authors.forename: Ram Kumar
authors.initials: RK
authors.lastname: Dhaked
mesh_terms: D000577:Amides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004305:Dose-Response Relationship, Drug; D055808:Drug Discovery; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D015394:Molecular Structure; D022621:Shiga Toxin / Q000037:antagonists & inhibitors*; D054852:Small Molecule Libraries / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014709:Vero Cells
chemical_list: D000577:Amides; D054852:Small Molecule Libraries; D022621:Shiga Toxin