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Characterization of Glucokinases from Pathogenic Free-Living Amoebae

Jillian E Milanes1, Jimmy Suryadi1, Neil P Monaghan1

  • 1Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson Universitygrid.26090.3d, Clemson, South Carolina, USA.

Antimicrobial Agents and Chemotherapy
|May 23, 2022
PubMed

Insights

Pathogenic free-living amoebae infections are deadly due to CNS involvement and lack of treatments. This study investigated Acanthamoeba castellanii (AcGlck) and Balamuthia mandrillaris (BmGlck) glucokinases as potential drug targets.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Parasitology

Background:

  • Infections by pathogenic free-living amoebae (FLA) like Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris cause severe central nervous system disease.
  • Current treatments for FLA infections are limited, leading to high mortality rates.
  • Targeting essential metabolic pathways, such as glucose metabolism, presents a potential therapeutic strategy.

Purpose of the Study:

  • To characterize the glucokinase enzymes from Acanthamoeba castellanii (AcGlck) and Balamuthia mandrillaris (BmGlck).
  • To compare the kinetic properties of AcGlck and BmGlck with each other and with human glucokinase (HsGlck).
  • To assess the potential of AcGlck and BmGlck as targets for novel anti-amoebic therapies.

Main Methods:

  • Enzyme kinetics assays were performed to determine kinetic parameters (Km values) for ATP and glucose.
  • Apparent Km values for ATP and glucose were measured for AcGlck, BmGlck, and HsGlck.
  • Sensitivity of AcGlck and BmGlck to small molecule inhibitors was evaluated.

Main Results:

  • AcGlck and BmGlck share 49.3% amino acid identity but exhibit distinct kinetic properties.
  • Both AcGlck and BmGlck have significantly higher apparent affinity for glucose compared to HsGlck.
  • AcGlck and BmGlck show differential sensitivity to small molecule inhibitors, complicating the development of pan-amoebic drugs.

Conclusions:

  • Glucokinases from Acanthamoeba and Balamuthia are viable targets for anti-amoebic drug development.
  • Differences in kinetic properties and inhibitor sensitivity between AcGlck, BmGlck, and HsGlck offer opportunities for selective targeting.
  • Developing inhibitors with broad activity against multiple FLA glucokinases may be challenging due to enzyme variations.
Keywords:
Acanthamoeba castellaniiBalamuthia mandrillarisNaegleria fowlerifree-living amoebaglucokinaseglycolysisinhibitorspentose phosphate pathway

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