Kennelly Corey, Prindle Arthur
Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
Center for Synthetic Biology, Northwestern University, Chicago, Illinois, USA.
mBio. 2024 Dec 11;15(12):e0243424. doi: 10.1128/mbio.02434-24. Epub 2024 Oct 30.
is an opportunistic pathogen that can salvage nucleobases from the environment to conserve nutrients that would otherwise be spent on nucleotide biosynthesis. However, little is known regarding the substrate specificity of the 13 putative nucleobase transporters in . Here, using a combination of genetic and chemical approaches, we report substrate identifications for 10 putative nucleobase transporters in . Specifically, we individually expressed each transporter in a genetic background lacking all 13 putative nucleobase transporters and quantified growth on a panel of 10 nucleobases as sole nitrogen sources. We confirmed these expression-based substrate identifications using targeted genetic knockouts. In a complementary approach, we utilized four toxic nucleobase antimetabolites to characterize antimicrobial activity in these same strains. We identified the sole allantoin transporter as well as transporters for guanine, xanthine, uric acid, cytosine, thymine, uracil, and dihydrouracil. Furthermore, we associated at least five nucleobase transporters with hypoxanthine, which has been recently reported to be an antibiofilm cue in . These results provide an initial characterization of the putative nucleobase transporters in , significantly advancing our understanding of nucleobase transport in this clinically relevant organism.
is a frequently multidrug-resistant opportunistic pathogen and one of the most common causes of healthcare-acquired infections. While nucleobases are known to support growth in nutrient-limited conditions, recent work showed that adenine and hypoxanthine can also decrease biofilm formation by disrupting c-di-GMP metabolism. Thus, nucleobase transport may be relevant to multiple aspects of biology and pathogenesis. However, there is currently little known about the transport of nucleobases in . Our work reports initial substrate identifications for 10 putative nucleobase transporters in , providing new tools to address previously difficult-to-test hypotheses relating to nucleobase transport in this organism.
是一种机会致病菌，它可以从环境中回收核碱基以节省营养物质，否则这些营养物质将用于核苷酸生物合成。然而，关于其中13种假定的核碱基转运蛋白的底物特异性知之甚少。在这里，我们结合遗传和化学方法，报告了其中10种假定的核碱基转运蛋白的底物鉴定结果。具体而言，我们在缺乏所有13种假定核碱基转运蛋白的遗传背景中单独表达每种转运蛋白，并以10种核碱基作为唯一氮源来量化生长情况。我们使用靶向基因敲除来确认这些基于表达的底物鉴定结果。在一种互补方法中，我们利用四种有毒的核碱基抗代谢物来表征这些相同菌株中的抗菌活性。我们鉴定出了唯一的尿囊素转运蛋白以及鸟嘌呤、黄嘌呤、尿酸、胞嘧啶、胸腺嘧啶、尿嘧啶和二氢尿嘧啶的转运蛋白。此外，我们将至少五种核碱基转运蛋白与次黄嘌呤联系起来，最近有报道称次黄嘌呤是其中的一种抗生物膜信号。这些结果提供了对其中假定核碱基转运蛋白的初步表征，显著推进了我们对这种临床相关生物体中核碱基转运的理解。
是一种常见的多重耐药机会致病菌，也是医疗保健相关感染的最常见原因之一。虽然已知核碱基在营养有限的条件下支持生长，但最近的研究表明，腺嘌呤和次黄嘌呤也可以通过破坏环二鸟苷酸代谢来减少生物膜形成。因此，核碱基转运可能与生物学和发病机制的多个方面相关。然而，目前关于核碱基在其中的转运知之甚少。我们的工作报告了其中10种假定核碱基转运蛋白的初步底物鉴定结果，为解决以前难以测试的与该生物体中核碱基转运相关的假设提供了新工具。
