Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Molecular Biology Program, New Mexico State University, Las Cruces, New Mexico, USA.
Mol Microbiol. 2022 Jun;117(6):1434-1446. doi: 10.1111/mmi.14918. Epub 2022 May 30.
Bacteria use various strategies to become antibiotic resistant. The molecular details of these strategies are not fully understood. We can increase our understanding by investigating the same strategies found in antibiotic-producing bacteria. In this work, we characterize the self-resistance protein Ecm16 encoded by echinomycin-producing bacteria. Ecm16 is a structural homolog of the nucleotide excision repair protein UvrA. Expression of ecm16 in the heterologous system Escherichia coli was sufficient to render resistance against echinomycin. Ecm16 binds DNA (double-stranded and single-stranded) using a nucleotide-independent binding mode. Ecm16's binding affinity for DNA increased by 1.7-fold when the DNA is intercalated with echinomycin. Ecm16 can render resistance against echinomycin toxicity independently of the nucleotide excision repair system. Similar to UvrA, Ecm16 has ATPase activity, and this activity is essential for Ecm16's ability to render echinomycin resistance. Notably, UvrA and Ecm16 were unable to complement each other's function. Together, our findings identify new mechanistic details of how a refurbished DNA repair protein Ecm16 can specifically render resistance to the DNA intercalator echinomycin.
细菌利用各种策略来产生抗生素耐药性。这些策略的分子细节尚不完全清楚。通过研究在产生抗生素的细菌中发现的相同策略，我们可以增加对这些策略的理解。在这项工作中，我们对来自棘霉素产生菌的自我抗性蛋白 Ecm16 进行了表征。Ecm16 是核苷酸切除修复蛋白 UvrA 的结构同源物。在异源系统大肠杆菌中表达 ecm16 足以使其对棘霉素产生抗性。Ecm16 使用非核苷酸依赖性结合模式结合 DNA（双链和单链）。当 DNA 与棘霉素嵌入时，Ecm16 对 DNA 的结合亲和力增加了 1.7 倍。Ecm16 可以独立于核苷酸切除修复系统产生对棘霉素毒性的抗性。与 UvrA 相似，Ecm16 具有 ATP 酶活性，并且这种活性对于 Ecm16 产生棘霉素抗性的能力是必需的。值得注意的是，UvrA 和 Ecm16 不能相互补充彼此的功能。总之，我们的发现确定了经过翻新的 DNA 修复蛋白 Ecm16 如何特异性地赋予 DNA 嵌入剂棘霉素抗性的新机制细节。
