Virtual medicinal chemistry: in silico pre-docking functional group transformation for discovery of novel inhibitors of botulinum toxin serotype A light chain.

A novel method for applying high-throughput docking to challenging metalloenzyme targets is described. The method utilizes information-based virtual transformation of library carboxylates to hydroxamic acids prior to docking, followed by compound acquisition, one-pot (two steps) chemical synthesis and in vitro screening. In two experiments targeting the botulinum neurotoxin serotype A metalloprotease light chain, hit rates of 32% and 18% were observed.

Antidotes to anthrax lethal factor intoxication. Part 3: Evaluation of core structures and further modifications to the C2-side chain.

Four core structures capable of providing sub-nanomolar inhibitors of anthrax lethal factor (LF) were evaluated by comparing the potential for toxicity, physicochemical properties, in vitro ADME profiles, and relative efficacy in a rat lethal toxin (LT) model of LF intoxication. Poor efficacy in the rat LT model exhibited by the phenoxyacetic acid series (3) correlated with low rat microsome and plasma stability. Specific molecular interactions contributing to the high affinity of inhibitors with a secondary amine in the C2-side chain were revealed by X-ray crystallography.

Small molecule pan-dengue and West Nile virus NS3 protease inhibitors.

Background: Dengue fever, dengue haemorrhagic fever, and dengue shock syndrome are caused by infections with any of the four serotypes of the dengue virus (DENV), and are an increasing global health risk. The related West Nile virus (WNV) causes significant morbidity and mortality as well, and continues to be a threat in endemic areas. Currently no FDA-approved vaccines or therapeutics are available to prevent or treat any of these infections.

Structural characterization of three novel hydroxamate-based zinc chelating inhibitors of the Clostridium botulinum serotype A neurotoxin light chain metalloprotease reveals a compact binding site resulting from 60/70 loop flexibility.

Neurotoxins synthesized by Clostridium botulinum bacteria (BoNT), the etiological agent of human botulism, are extremely toxic proteins making them high-risk agents for bioterrorism. Small molecule inhibitor development has been focused on the light chain zinc-dependent metalloprotease domain of the neurotoxin, an effort that has been hampered by its relatively flexible active site. Developed in concert with structure--activity relationship studies, the X-ray crystal structures of the complex of BoNT serotype A light chain (BoNT/A LC) with three different micromolar-potency hydroxamate-based inhibitors are reported here.

Antidotes to anthrax lethal factor intoxication. Part 2: structural modifications leading to improved in vivo efficacy.

New anthrax lethal factor inhibitors (LFIs) were designed based upon previously identified potent inhibitors 1a and 2. Combining the new core structures with modifications to the C2-side chain yielded analogs with improved efficacy in the rat lethal toxin model.

Antidotes to anthrax lethal factor intoxication. Part 1: Discovery of potent lethal factor inhibitors with in vivo efficacy.

Sub-nanomolar small molecule inhibitors of anthrax lethal factor have been identified using SAR and Merck L915 (4) as a model compound. One of these compounds (16) provided 100% protection in a rat lethal toxin model of anthrax disease.

Structure-based design of novel human Pin1 inhibitors (I).

Pin1 is a member of the cis-trans peptidyl-prolyl isomerase family with potential anti-cancer therapeutic value. Here we report structure-based de novo design and optimization of novel Pin1 inhibitors. Without a viable lead from internal screenings, we designed a series of novel Pin1 inhibitors by interrogating and exploring a protein crystal structure of Pin1.

Crystal structures of bacterial FabH suggest a molecular basis for the substrate specificity of the enzyme.

FabH (beta-ketoacyl-acyl carrier protein synthase III) is unique in that it initiates fatty acid biosynthesis, is inhibited by long-chain fatty acids providing means for feedback control of the process, and dictates the fatty acid profile of the organism by virtue of its substrate specificity. We report the crystal structures of bacterial FabH enzymes from four different pathogenic species: Enterococcus faecalis, Haemophilus influenzae, Staphylococcus aureus and Escherichia coli. Structural data on the enzyme from different species show important differences in the architecture of the substrate-binding sites that parallel the inter-species diversity in the substrate specificities of these enzymes.

Structure-based design and synthesis of novel macrocyclic pyrazolo[1,5-a] [1,3,5]triazine compounds as potent inhibitors of protein kinase CK2 and their anticancer activities.

A series of macrocyclic derivatives has been designed and synthesized based on the X-ray co-crystal structures of pyrazolo[1,5-a] [1,3,5]triazines with corn CK2 (cCK2) protein. Bioassays demonstrated that these macrocyclic pyrazolo[1,5-a] [1,3,5]triazine compounds are potent CK2 inhibitors with K(i) around 1.0 nM and strongly inhibit cancer cell growth with IC(50) as low as approximately 100 nM.

Structure-based design, synthesis, and study of pyrazolo[1,5-a][1,3,5]triazine derivatives as potent inhibitors of protein kinase CK2.

The structure-based design, synthesis, and anticancer activity of novel inhibitors of protein kinase CK2 are described. Using pyrazolo[1,5-a][1,3,5]triazine as the core scaffold, a structure-guided series of modifications provided pM inhibitors with microM-level cytotoxic activity in cell-based assays with prostate and colon cancer cell lines.

Structure-based design, synthesis, and study of potent inhibitors of beta-ketoacyl-acyl carrier protein synthase III as potential antimicrobial agents.

Fatty acid biosynthesis is essential for bacterial survival. Components of this biosynthetic pathway have been identified as attractive targets for the development of new antibacterial agents. FabH, beta-ketoacyl-ACP synthase III, is a particularly attractive target, since it is central to the initiation of fatty acid biosynthesis and is highly conserved among Gram-positive and -negative bacteria.

Crystal structure of human ABAD/HSD10 with a bound inhibitor: implications for design of Alzheimer's disease therapeutics.

The enzyme 17beta-hydroxysteroid dehydrogenase type 10 (HSD10), also known as amyloid beta-peptide-binding alcohol dehydrogenase (ABAD), has been implicated in the development of Alzheimer's disease. This protein, a member of the short-chain dehydrogenase/reductase family of enzymes, has been shown to bind beta-amyloid and to participate in beta-amyloid neurotoxicity. We have determined the crystal structure of human ABAD/HSD10 complexed with NAD(+) and an inhibitory small molecule.

Structure-based design, synthesis, and antimicrobial activity of purine derived SAH/MTA nucleosidase inhibitors.

The structure-based design, synthesis, and biological activity of novel inhibitors of S-adenosyl homocysteine/methylthioadenosine (SAH/MTA) nucleosidase are described. Using 6-substituted purine and deaza purines as the core scaffolds, a systematic and structure guided series of modifications provided low nM inhibitors with broad-spectrum antimicrobial activity.

Structure-based design, synthesis, and antimicrobial activity of indazole-derived SAH/MTA nucleosidase inhibitors.

The structure-based design, synthesis, and biological activity of a novel indazole-containing inhibitor series for S-adenosyl homocysteine/methylthioadenosine (SAH/MTA) nucleosidase are described. Use of 5-aminoindazole as the core scaffold provided a structure-guided series of low nanomolar inhibitors with broad-spectrum antimicrobial activity. The implementation of structure-based methodologies provided a 6000-fold increase in potency over a short timeline (several months) and an economy of synthesized compounds.