SAR studies for a new class of antibacterial NAD biosynthesis inhibitors.

A new lead class of antibacterial drug-like NAD synthetase (NADs) inhibitors was previously identified from a virtual screening study. Here a solution-phase synthetic library of 76 compounds, analogs of the urea-sulfonamide 5838, was synthesized in parallel to explore SAR on the sulfonamide aryl group. All library members were tested for enzyme inhibition against NADs and nicotinic acid mononucleotide adenylyltransferase (NaMNAT), the last two enzymes in the biosynthesis of NAD, and for growth inhibition in a Bacillus anthracis antibacterial assay.

Virtual screening to identify lead inhibitors for bacterial NAD synthetase (NADs).

Virtual screening was employed to identify new drug-like inhibitors of NAD synthetase (NADs) as antibacterial agents. Four databases of commercially available compounds were docked against three subsites of the NADs active site using FlexX in conjunction with CScore. Over 200 commercial compounds were purchased and evaluated in enzyme inhibition and antibacterial assays.

The functional molecular mass of the Pasteurella hyaluronan synthase is a monomer.

Hyaluronan (HA), a linear polysaccharide composed of beta1,3-GlcNAc-beta1,4-GlcUA repeats, is found in the extracellular matrix of vertebrate tissues as well as the capsule of several pathogenic bacteria. All known HA synthases (HASs) are dual-action glycosyltransferases that catalyze the addition of two different sugars from UDP-linked precursors to the growing HA chain. The bacterial hyaluronan synthase, PmHAS from Gram-negative Pasteurella multocida, is a 972-residue membrane-associated protein.

Functional characterization of PmHS1, a Pasteurella multocida heparosan synthase.

Heparosan synthase 1 (PmHS1) from Pasteurella multocida Type D is a dual action glycosyltransferase enzyme that transfers monosaccharide units from uridine diphospho (UDP) sugar precursors to form the polysaccharide heparosan (N-acetylheparosan), which is composed of alternating (-alpha4-GlcNAc-beta1,4-GlcUA-1-) repeats. We have used molecular genetic means to remove regions nonessential for catalytic activity from the amino- and the carboxyl-terminal regions as well as characterized the functional regions involved in GlcUA-transferase activity and in GlcNAc-transferase activity. Mutation of either one of the two regions containing aspartate-X-aspartate (DXD) residue-containing motifs resulted in complete or substantial loss of heparosan polymerizing activity.