Lujan Scott A, Guogas Laura M, Ragonese Heather, Matson Steven W, Redinbo Matthew R
Department of Chemistry, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599-3290, USA.
Proc Natl Acad Sci U S A. 2007 Jul 24;104(30):12282-7. doi: 10.1073/pnas.0702760104. Epub 2007 Jul 13.
Conjugative transfer of plasmid DNA via close cell-cell junctions is the main route by which antibiotic resistance genes spread between bacterial strains. Relaxases are essential for conjugative transfer and act by cleaving DNA strands and forming covalent phosphotyrosine linkages. Based on data indicating that multityrosine relaxase enzymes can accommodate two phosphotyrosine intermediates within their divalent metal-containing active sites, we hypothesized that bisphosphonates would inhibit relaxase activity and conjugative DNA transfer. We identified bisphosphonates that are nanomolar inhibitors of the F plasmid conjugative relaxase in vitro. Furthermore, we used cell-based assays to demonstrate that these compounds are highly effective at preventing DNA transfer and at selectively killing cells harboring conjugative plasmids. Two potent inhibitors, clodronate and etidronate, are already clinically approved to treat bone loss. Thus, the inhibition of conjugative relaxases is a potentially novel antimicrobial approach, one that selectively targets bacteria capable of transferring antibiotic resistance and generating multidrug resistant strains.
通过紧密的细胞间连接进行质粒DNA的接合转移是抗生素抗性基因在细菌菌株间传播的主要途径。松弛酶对于接合转移至关重要，其作用方式是切割DNA链并形成共价磷酸酪氨酸连接。基于数据表明多酪氨酸松弛酶能够在其含二价金属的活性位点容纳两个磷酸酪氨酸中间体，我们推测双膦酸盐会抑制松弛酶活性和接合性DNA转移。我们鉴定出在体外是F质粒接合松弛酶的纳摩尔抑制剂的双膦酸盐。此外，我们使用基于细胞的试验来证明这些化合物在防止DNA转移和选择性杀死携带接合性质粒的细胞方面非常有效。两种强效抑制剂，氯膦酸盐和依替膦酸盐，已在临床上被批准用于治疗骨质流失。因此，抑制接合松弛酶是一种潜在的新型抗菌方法，一种选择性靶向能够转移抗生素抗性并产生多重耐药菌株的细菌的方法。
