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System for Efficacy and Cytotoxicity Screening of Inhibitors Targeting Intracellular Mycobacterium tuberculosis
Published on: April 5, 2017
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Transition metal cation inhibition of Mycobacterium tuberculosis esterase RV0045C
Isobel E Bowles1, Emily H Pool1, Benjamin S Lancaster1
1Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA.
Protein Science : a Publication of the Protein Society
|April 29, 2021
Summary
Mycobacterium tuberculosis virulence is metal-dependent. Divalent metals like copper and zinc allosterically inhibit the Rv0045c enzyme by binding to a flexible loop, impacting its activity.
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- Mycobacterium tuberculosis virulence relies on metal availability, influencing infection states.
- Rv0045c is a proposed metabolic serine hydrolase whose stability depends on divalent metals.
Purpose of the Study:
- To investigate the divalent metal inhibition profile of Rv0045c's enzymatic activity.
- To structurally elucidate the mechanism of allosteric metal regulation in Rv0045c.
Main Methods:
- Enzyme activity assays with various divalent metal cations.
- X-ray crystallography to determine Rv0045c structures with and without Zn2+.
- Site-directed mutagenesis to identify key residues involved in metal binding.
Main Results:
- Specific divalent transition metals (Cu2+, Zn2+, Ni2+, Co2+) strongly inhibited Rv0045c activity.
- Metal cations bind allosterically, primarily affecting the catalytic rate (kcat).
- Structural analysis revealed a dynamic loop and chelating residues (H202, E204) responsible for Zn2+ binding and inhibition.
Conclusions:
- Rv0045c activity is dynamically regulated by divalent metals through allosteric inhibition.
- This study provides the first structural evidence of divalent metal allosteric regulation in serine hydrolases.
- Understanding this mechanism could offer new targets for controlling M. tuberculosis infection.
