单链DNA结合蛋白(SSB)通过结合和稳定单链DNA(ssDNA)中间体在DNA代谢中起关键作用。通过它们在DNA复制中的多方面作用,重组,修复,复制重新启动,和其他细胞过程,SSB成为维持基因组完整性的核心角色。这些属性共同将SSB定位为基因组完整性的基本守护者,与一系列不同的蛋白质建立相互作用。与大肠杆菌不同,只包含一种类型的SSB,一些细菌有两个同源SSB,称为SsbA和SsbB。在这项研究中,我们将金黄色葡萄球菌SsbA(SaSsbA)鉴定为抗癌药物5-氟尿嘧啶(5-FU)结合蛋白的新成员,从而扩大了5-FU相互作用组的范围以涵盖该DNA复制蛋白。要研究绑定模式,我们用5-FU在2.3µ(PDBID7YM1)处解决了复杂的晶体结构。甘油结合的SaSsbA的结构也在1.8进行了测定(PDBID8GW5)。发现5-FU和SaSsbA之间的相互作用涉及R18、P21、V52、F54、Q78、R80、E94和V96。根据突变和结构分析的集体结果,很明显,SaSsbA与5-FU的绑定模式与SaSsbB的绑定模式不同。这种复杂的结构也有可能提供关于5-FU如何结合和阻碍人类类似蛋白质的有价值的理解。特别是在癌症相关的信号通路内。利用甘油和5-FU结合位点提供的信息,SaSsbA的复杂结构将几个相互作用残基的潜在生存能力带到了最前沿,作为旨在减少SaSsbA活性的治疗干预措施的潜在目标。承认微生物群影响宿主对5-FU反应的能力,迫切需要进一步研究以重新审视细菌和人类SSB在抗癌治疗领域中的作用。
Single-stranded DNA-binding proteins (SSBs) play a crucial role in DNA metabolism by binding and stabilizing single-stranded DNA (ssDNA) intermediates. Through their multifaceted roles in DNA replication, recombination, repair, replication restart, and other cellular processes, SSB emerges as a central player in maintaining genomic integrity. These attributes collectively position SSBs as essential guardians of genomic integrity, establishing interactions with an array of distinct proteins. Unlike Escherichia coli, which contains only one type of SSB, some bacteria have two paralogous SSBs, referred to as SsbA and SsbB. In this study, we identified Staphylococcus aureus SsbA (SaSsbA) as a fresh addition to the roster of the anticancer drug 5-fluorouracil (5-FU) binding proteins, thereby expanding the ambit of the 5-FU interactome to encompass this DNA replication protein. To investigate the binding mode, we solved the complexed crystal structure with 5-FU at 2.3 Å (PDB ID 7YM1). The structure of glycerol-bound SaSsbA was also determined at 1.8 Å (PDB ID 8GW5). The interaction between 5-FU and SaSsbA was found to involve R18, P21, V52, F54, Q78, R80, E94, and V96. Based on the collective results from mutational and structural analyses, it became evident that SaSsbA\'s mode of binding with 5-FU diverges from that of SaSsbB. This complexed structure also holds the potential to furnish valuable comprehension regarding how 5-FU might bind to and impede analogous proteins in humans, particularly within cancer-related signaling pathways. Leveraging the information furnished by the glycerol and 5-FU binding sites, the complexed structures of SaSsbA bring to the forefront the potential viability of several interactive residues as potential targets for therapeutic interventions aimed at curtailing SaSsbA activity. Acknowledging the capacity of microbiota to influence the host\'s response to 5-FU, there emerges a pressing need for further research to revisit the roles that bacterial and human SSBs play in the realm of anticancer therapy.