Bactericidal activity of PA-824 against Mycobacterium tuberculosis under anaerobic conditions and computational analysis of its novel analogues against mutant Ddn receptor

BMC Microbiology

Research Article

Ramaian Santhaseela Anand¹  Sulochana Somasundaram²  Chinnambedu N Paramasivan³  Perumal Venkatesan⁴ 

[1] Centre for Biotechnology, Anna University, Chennai, India;Department of Biotechnology, Sri Venkateswara College of Engineering, Sriperumbudur, India;Foundation for Innovative New Diagnostics, Flat No. 6-14 (excluding No. 7), 9th floor, Vijaya Building, 17-Barakhamba Road, 110 001, New Delhi, India;National Institute for Research in Tuberculosis, Chennai, India;

关键词: Bactericidal activity;    Mycobacterium tuberculosis;    Anaerobic activity;    Docking;    Ddn;    PA-824;   

DOI  :  10.1186/1471-2180-13-218

 received in 2013-02-12, accepted in 2013-09-27,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundThe resurgence of multi-drug resistant tuberculosis (MDR-TB) and HIV associated tuberculosis (TB) are of serious global concern. To contain this situation, new anti-tuberculosis drugs and reduced treatment regimens are imperative. Recently, a nitroimidazole, PA-824, has been shown to be active against both replicating and non-replicating bacteria. It is activated by the enzyme Deazaflavin-dependent nitroreductase (Ddn) present in Mycobacterium tuberculosis which catalyzes the reduction of PA-824, resulting in the release of lethal reactive nitrogen species (RNS) within the bacteria. In this context, PA-824 was analyzed for its activity against latent tuberculosis under anaerobic conditions and compared with rifampicin (RIF) and pyrazinamide (PZA). Recent mutagenesis studies have identified A76E mutation which affects the above mentioned catalysis and leads to PA-824 resistance. Hence, novel analogues which could cope up with their binding to mutant Ddn receptor were also identified through this study.ResultsPA-824 at an optimum concentration of 12.5 μg/ml showed enhanced bactericidal activity, resulting in 0 CFU/ml growth when compared to RIF and PZA at normal pH and anaerobic condition. Further docking studies revealed that a combinatorial structure of PA-824 conjugated with moxifloxacin (ligand 8) has the highest binding affinity with the wild type and mutant Ddn receptor.ConclusionsPA-824 has been demonstrated to have better activity under anaerobic condition at 12.5 μg/ml, indicating an optimized dose that is required for overcoming the detoxifying mechanisms of M. tuberculosis and inducing its death. Further, the development of resistance through A76E mutation could be overcome through the in silico evolved ligand 8.

【 授权许可】

Unknown   
© Somasundaram et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.