Panda Pragnya, Taviti Ashoka Chary, Satpati Suresh, Kar Mitali Madhusmita, Dixit Anshuman, Beuria Tushar Kant
Institute of Life Sciences, Nalco Square, Bhubaneswar, Odisha 751023, India.
Institute of Life Sciences, Nalco Square, Bhubaneswar, Odisha 751023, India Manipal University, Manipal, Karnataka 576104, India.
Biochem J. 2015 Nov 1;471(3):335-46. doi: 10.1042/BJ20150467. Epub 2015 Aug 18.
The increase in antibiotic resistance has become a major health concern in recent times. It is therefore essential to identify novel antibacterial targets as well as discover and develop new antibacterial agents. FtsZ, a highly conserved bacterial protein, is responsible for the initiation of cell division in bacteria. The functions of FtsZ inside cells are tightly regulated and any perturbation in its functions leads to inhibition of bacterial division. Recent reports indicate that small molecules targeting the functions of FtsZ may be used as leads to develop new antibacterial agents. To identify small molecules targeting FtsZ and inhibiting bacterial division, we screened a U.S. FDA (Food and Drug Administration)-approved drug library of 800 molecules using an independent computational, biochemical and microbial approach. From this screen, we identified doxorubicin, an anthracycline molecule that inhibits Escherichia coli division and forms filamentous cells. A fluorescence-binding assay shows that doxorubicin interacts strongly with FtsZ. A detailed biochemical analysis demonstrated that doxorubicin inhibits FtsZ assembly and its GTPase activity through binding to a site other than the GTP-binding site. Furthermore, using molecular docking, we identified a probable doxorubicin-binding site in FtsZ. A number of single amino acid mutations at the identified binding site in FtsZ resulted in a severalfold decrease in the affinity of FtsZ for doxorubicin, indicating the importance of this site for doxorubicin interaction. The present study suggests the presence of a novel binding site in FtsZ that interacts with the small molecules and can be targeted for the screening and development of new antibacterial agents.
近年来，抗生素耐药性的增加已成为一个主要的健康问题。因此，识别新的抗菌靶点以及发现和开发新的抗菌剂至关重要。FtsZ是一种高度保守的细菌蛋白，负责细菌细胞分裂的起始。FtsZ在细胞内的功能受到严格调控，其功能的任何扰动都会导致细菌分裂受到抑制。最近的报道表明，靶向FtsZ功能的小分子可能被用作开发新抗菌剂的先导物。为了识别靶向FtsZ并抑制细菌分裂的小分子，我们使用独立的计算、生化和微生物方法，筛选了一个由800种分子组成的美国食品药品监督管理局（FDA）批准的药物库。通过该筛选，我们鉴定出阿霉素，一种蒽环类分子，它能抑制大肠杆菌分裂并形成丝状细胞。荧光结合试验表明，阿霉素与FtsZ强烈相互作用。详细的生化分析表明，阿霉素通过结合到GTP结合位点以外的位点来抑制FtsZ组装及其GTP酶活性。此外，通过分子对接，我们在FtsZ中确定了一个可能的阿霉素结合位点。FtsZ中已确定的结合位点处的多个单氨基酸突变导致FtsZ对阿霉素的亲和力下降了几倍，表明该位点对于阿霉素相互作用的重要性。本研究表明FtsZ中存在一个新的结合位点，该位点与小分子相互作用，可作为筛选和开发新抗菌剂的靶点。
