Probing the Robustness of Inhibitors of Tuberculosis Aminoglycoside Resistance Enzyme Eis by Mutagenesis

ACS Infect Dis. 2019 Oct 11;5(10):1772-1778. doi: 10.1021/acsinfecdis.9b00228. Epub 2019 Aug 21.


Each year, millions of people worldwide contract tuberculosis (TB), the deadliest infection. The spread of infections with drug-resistant strains of Mycobacterium tuberculosis (Mtb) that are refractory to treatment poses a major global challenge. A major cause of resistance to antitubercular drugs of last resort, aminoglycosides, is overexpression of the Eis (enhanced intracellular survival) enzyme of Mtb, which inactivates aminoglycosides by acetylating them. We showed previously that this inactivation of aminoglycosides could be overcome by our recently reported Eis inhibitors that are currently in development as potential aminoglycoside adjunctive therapeutics against drug-resistant TB. To interrogate the robustness of the Eis inhibitors, we investigated the enzymatic activity of Eis and its inhibition by Eis inhibitors from three different structural families for nine single-residue mutants of Eis, including those found in the clinic. Three engineered mutations of the substrate binding site, D26A, W36A, and F84A, abolished inhibitor binding while compromising Eis enzymatic activity 2- to 3-fold. All other Eis mutants, including clinically observed ones, were potently inhibited by at least one inhibitor. This study helps position us one step ahead of Mtb resistance to Eis inhibitors as they are being developed for TB therapy.

Keywords: acetylation; enzyme inhibitor; kanamycin; mutations; mycobacteria.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Acetyltransferases
  • Aminoglycosides / metabolism*
  • Aminoglycosides / pharmacology
  • Antigens, Bacterial / drug effects*
  • Antigens, Bacterial / genetics*
  • Antigens, Bacterial / metabolism
  • Antitubercular Agents / chemistry*
  • Antitubercular Agents / pharmacology
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Binding Sites / genetics
  • Drug Resistance, Bacterial / drug effects
  • Drug Resistance, Bacterial / genetics
  • Enzyme Inhibitors / chemistry*
  • Enzyme Inhibitors / pharmacology
  • Kanamycin / chemistry
  • Kanamycin / pharmacology
  • Kinetics
  • Models, Molecular
  • Mutagenesis*
  • Mutation
  • Mycobacterium tuberculosis / drug effects*
  • Mycobacterium tuberculosis / enzymology*
  • Mycobacterium tuberculosis / genetics
  • Protein Conformation
  • Tuberculosis / drug therapy
  • Tuberculosis, Multidrug-Resistant


  • Aminoglycosides
  • Antigens, Bacterial
  • Antitubercular Agents
  • Bacterial Proteins
  • Enzyme Inhibitors
  • Kanamycin
  • Acetyltransferases
  • Eis protein, Mycobacterium tuberculosis