Targeting the chromosome partitioning protein ParA in tuberculosis drug discovery.
J Antimicrob Chemother 2010;
65:2347-58. [PMID:
20810423 PMCID:
PMC2980951 DOI:
10.1093/jac/dkq311]
[Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 07/07/2010] [Accepted: 07/19/2010] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE
To identify inhibitors of the essential chromosome partitioning protein ParA that are active against Mycobacterium tuberculosis.
METHODS
Antisense expression of the parA orthologue MSMEG_6939 was induced on the Mycobacterium smegmatis background. Screening of synthetic chemical libraries was performed to identify compounds with higher anti-mycobacterial activity in the presence of parA antisense. Differentially active compounds were validated for specific inhibition of purified ParA protein from M. tuberculosis (Rv3918c). ParA inhibitors were then characterized for their activity towards M. tuberculosis in vitro.
RESULTS
Under a number of culture conditions, parA antisense expression in M. smegmatis resulted in reduced growth. This effect on growth provided a basis for the detection of compounds that increased susceptibility to expression of parA antisense. Two compounds identified from library screening, phenoxybenzamine and octoclothepin, also inhibited the in vitro ATPase activity of ParA from M. tuberculosis. Structural in silico analyses predict that phenoxybenzamine and octoclothepin undergo interactions compatible with the active site of ParA. Octoclothepin exhibited significant bacteriostatic activity towards M. tuberculosis.
CONCLUSIONS
Our data support the use of whole-cell differential antisense screens for the discovery of inhibitors of specific anti-tubercular drug targets. Using this approach, we have identified an inhibitor of purified ParA and whole cells of M. tuberculosis.
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