Structure, Biophysics and FBLG, Discovery Sciences, R&D, AstraZeneca, Gothenburg, Sweden.
Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
ACS Chem Biol. 2020 Nov 20;15(11):2885-2895. doi: 10.1021/acschembio.0c00423. Epub 2020 Nov 9.
The alarming growth of antibiotic resistance that is currently ongoing is a serious threat to human health. One of the most promising novel antibiotic targets is MraY (phospho-MurNAc-pentapeptide-transferase), an essential enzyme in bacterial cell wall synthesis. Through recent advances in biochemical research, there is now structural information available for MraY, and for its human homologue GPT (GlcNAc-1-P-transferase), that opens up exciting possibilities for structure-based drug design. The antibiotic compound tunicamycin is a natural product inhibitor of MraY that is also toxic to eukaryotes through its binding to GPT. In this work, we have used tunicamycin and modified versions of tunicamycin as tool compounds to explore the active site of MraY and to gain further insight into what determines inhibitor potency. We have investigated tunicamycin variants where the following motifs have been modified: the length and branching of the tunicamycin fatty acyl chain, the saturation of the fatty acyl chain, the 6″-hydroxyl group of the GlcNAc ring, and the ring structure of the uracil motif. The compounds are analyzed in terms of how potently they bind to MraY, inhibit the activity of the enzyme, and affect the protein thermal stability. Finally, we rationalize these results in the context of the protein structures of MraY and GPT.
目前正在发生的抗生素耐药性的惊人增长对人类健康构成了严重威胁。最有前途的新型抗生素靶标之一是 MraY（磷酸-MurNAc-五肽转移酶），它是细菌细胞壁合成中的一种必需酶。通过最近在生化研究方面的进展，现在已经获得了 MraY 及其人类同源物 GPT（GlcNAc-1-P-转移酶）的结构信息，这为基于结构的药物设计开辟了令人兴奋的可能性。抗生素化合物衣霉素是 MraY 的天然产物抑制剂，通过与 GPT 结合对真核生物也具有毒性。在这项工作中，我们使用衣霉素和衣霉素的修饰版本作为工具化合物来探索 MraY 的活性位点，并进一步深入了解是什么决定了抑制剂的效力。我们研究了衣霉素变体，其中修饰了以下模体：衣霉素脂肪酸酰链的长度和支化、脂肪酸酰链的饱和度、GlcNAc 环的 6″-羟基和尿嘧啶模体的环结构。根据这些化合物与 MraY 的结合能力、抑制酶活性以及影响蛋白质热稳定性的能力来分析它们。最后，我们根据 MraY 和 GPT 的蛋白质结构来合理化这些结果。
