Abstract：
Ceramide synthases (CerSs) play crucial roles in sphingolipid metabolism and have emerged as promising drug targets for metabolic diseases, cancers, and antifungal therapy. However, the therapeutic targeting of CerSs has been hindered by a limited understanding of their inhibition mechanisms by small molecules. Fumonisin B1 (FB1) has been extensively studied as a potent inhibitor of eukaryotic CerSs. In this study, we characterize the inhibition mechanism of FB1 on yeast CerS (yCerS) and determine the structures of both FB1-bound and N-acyl-FB1-bound yCerS. Through our structural analysis and the observation of N-acylation of FB1 by yCerS, we propose a potential ping-pong catalytic mechanism for FB1 N-acylation by yCerS. Lastly, we demonstrate that FB1 exhibits lower binding affinity for yCerS compared to the C26- coenzyme A (CoA) substrate, suggesting that the potent inhibitory effect of FB1 on yCerS may primarily result from the N-acyl-FB1 catalyzed by yCerS, rather than through direct binding of FB1.
摘要：
神经酰胺合酶（CerSs）在鞘脂代谢中起着至关重要的作用，并已成为代谢性疾病的有希望的药物靶标。癌症,和抗真菌治疗。然而,小分子对CerSs抑制机制的理解有限,阻碍了CerSs的治疗靶向.伏马菌素B1（FB1）已被广泛研究为真核生物CerSs的有效抑制剂。在这项研究中,我们表征了FB1对酵母CerS（yCerS）的抑制机制，并确定了FB1结合和N-酰基FB1结合的yCerS的结构。通过我们的结构分析和YCerS对FB1的N-酰化的观察，我们提出了一种通过yCerS进行FB1N-酰化的潜在乒乓催化机理。最后,我们证明，与C26-辅酶A（CoA）底物相比，FB1对yCerS的结合亲和力较低，表明FB1对yCerS的有效抑制作用可能主要来自yCerS催化的N-酰基-FB1，而不是通过FB1的直接结合。
