Transition metal cation inhibition of Mycobacterium tuberculosis esterase RV0045C.

Autor: Bowles IE; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Pool EH; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Lancaster BS; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Lawson EK; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Savas CP; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Kartje ZJ; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Severinac L; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Cho DH; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Macbeth MR; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Johnson RJ; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA., Hoops GC; Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA.
Jazyk: angličtina
Zdroj: Protein science : a publication of the Protein Society [Protein Sci] 2021 Aug; Vol. 30 (8), pp. 1554-1565. Date of Electronic Publication: 2021 Jun 04.
DOI: 10.1002/pro.4089
Abstrakt: Mycobacterium tuberculosis virulence is highly metal-dependent with metal availability modulating the shift from the dormant to active states of M. tuberculosis infection. Rv0045c from M. tuberculosis is a proposed metabolic serine hydrolase whose folded stability is dependent on divalent metal concentration. Herein, we measured the divalent metal inhibition profile of the enzymatic activity of Rv0045c and found specific divalent transition metal cations (Cu 2+  ≥ Zn 2+  > Ni 2+  > Co 2+ ) strongly inhibited its enzymatic activity. The metal cations bind allosterically, largely affecting values for k cat rather than K M . Removal of the artificial N-terminal 6xHis-tag did not change the metal-dependent inhibition, indicating that the allosteric inhibition site is native to Rv0045c. To isolate the site of this allosteric regulation in Rv0045c, the structures of Rv0045c were determined at 1.8 Å and 2.0 Å resolution in the presence and absence of Zn 2+ with each structure containing a previously unresolved dynamic loop spanning the binding pocket. Through the combination of structural analysis with and without zinc and targeted mutagenesis, this metal-dependent inhibition was traced to multiple chelating residues (H202A/E204A) on a flexible loop, suggesting dynamic allosteric regulation of Rv0045c by divalent metals. Although serine hydrolases like Rv0045c are a large and diverse enzyme superfamily, this is the first structural confirmation of allosteric regulation of their enzymatic activity by divalent metals.
(© 2021 The Protein Society.)
Databáze: MEDLINE
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