Identification of Small Molecule Inhibitors against <i>Staphylococcus aureus</i> Dihydroorotase via HTS

Identification of Small Molecule Inhibitors against <i>Staphylococcus aureus</i> Dihydroorotase via HTS

Drug-resistant <i>Staphylococcus aureus</i> is an imminent threat to public health, increasing the importance of drug discovery utilizing unexplored bacterial pathways and enzyme targets. <i>De novo</i> pyrimidine biosynthesis is a specialized, highly conserved pathway implic...

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Bibliographic Details
Main Authors: Amy J. Rice, Russell P. Pesavento, Jinhong Ren, Isoo Youn, Youngjin Kwon, Kassapa Ellepola, Chun-Tao Che, Michael E. Johnson, Hyun Lee
Format: Article
Language:English
Published: MDPI AG 2021-09-01
Series:International Journal of Molecular Sciences
Subjects:
<i>S. aureus</i>
antimicrobial
dihydroorotase
Class I DHOase
inhibitors
Online Access:https://www.mdpi.com/1422-0067/22/18/9984
Description
Summary:Drug-resistant <i>Staphylococcus aureus</i> is an imminent threat to public health, increasing the importance of drug discovery utilizing unexplored bacterial pathways and enzyme targets. <i>De novo</i> pyrimidine biosynthesis is a specialized, highly conserved pathway implicated in both the survival and virulence of several clinically relevant pathogens. Class I dihydroorotase (DHOase) is a separate and distinct enzyme present in gram positive bacteria (i.e., <i>S. aureus</i>, <i>B. anthracis</i>) that converts carbamoyl-aspartate (Ca-asp) to dihydroorotate (DHO)—an integral step in the <i>de novo</i> pyrimidine biosynthesis pathway. This study sets forth a high-throughput screening (HTS) of 3000 fragment compounds by a colorimetry-based enzymatic assay as a primary screen, identifying small molecule inhibitors of <i>S. aureus</i> DHOase (<i>Sa</i>DHOase), followed by hit validation with a direct binding analysis using surface plasmon resonance (SPR). Competition SPR studies of six hit compounds and eight additional analogs with the substrate Ca-asp determined the best compound to be a competitive inhibitor with a <i>K</i><sub>D</sub> value of 11 µM, which is 10-fold tighter than Ca-asp. Preliminary structure–activity relationship (SAR) provides the foundation for further structure-based antimicrobial inhibitor design against <i>S. aureus</i>.
ISSN:1661-6596
1422-0067

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