Jiao Li,Ruiyang Li,Na Shang,Yan Men,Yi Cai,Yan Zeng,Weidong Liu,Jiangang Yang,Yuanxia Sun
The addition of the O-linked N-acetylglucosamine (O-GlcNAc) is a significant modification for active molecules, such as proteins, carbohydrates, and natural products. However, the synthesis of terpenoid glycoside derivatives decorated with GlcNAc remains a challenging task due to the absence of glycosyltransferases, key enzymes for catalyzing the transfer of GlcNAc to terpenoids. In this study, we demonstrated that the enzyme mutant UGT74AC1T79Y/L48M/R28H/L109I/S15A/M76L/H47R efficiently transferred GlcNAc from uridine diphosphate (UDP)-GlcNAc to a variety of terpenoids. This powerful enzyme was employed to synthesize GlcNAc-decorated derivatives of terpenoids, including mogrol, steviol, andrographolide, protopanaxadiol, glycyrrhetinic acid, ursolic acid, and betulinic acid for the first time. To unravel the mechanism of UDP-GlcNAc recognition, we determined the X-ray crystal structure of the inactivated mutant UGT74AC1His18A/Asp111A in complex with UDP-GlcNAc at a resolution of 1.66 Å. Through molecular dynamic simulation and activity analysis, we revealed the molecular mechanism and catalytically important amino acids directly involved in the recognition of UDP-GlcNAc. Overall, this study not only provided a potent biocatalyst capable of glycodiversifying natural products but also elucidated the structural basis for UDP-GlcNAc recognition by glycosyltransferases.
Dan Zhou,Dingru Li,Caimei Zhong,Qiang Li,Peixian Chen,Shuqing Yang,Herong Liang,Zhiyan Chen,Han He,Hua Zhang,Xiaohong Zeng,Mo Chen,Yingxin Lin,Meng Xu,Xingyin Liu,Mengyun Cai,Yuhua Deng
The gut microbiome is increasingly linked to breast cancer (BC) progression; however, specific microbial metabolites and their direct mechanistic connections to oncogenic signalling remain poorly defined. Here, using multi-omics analyses in treatment-naïve patients with BC, we identified gut microbiota-derived uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) as a circulating oncometabolite associated with therapeutic response. We further showed that Ruminococcus lactaris is a key intestinal commensal capable of de novo UDP-GlcNAc biosynthesis, and that microbial-derived UDP-GlcNAc acts as an independent tumour-promoting metabolite, even though the host hexosamine pathways generate the majority of circulating UDP-GlcNAc pools. Mechanistically, UDP-GlcNAc systemically activates O-GlcNAc transferase (OGT), stabilizing the transcription factor NFIB, and triggers a feed-forward loop that upregulates OGT and the proto-oncogene KIT , thereby driving BC progression. Genetic or pharmacological inhibition of OGT disrupts this signaling axis and suppresses tumour growth, even in the presence of UDP-GlcNAc–producing bacteria. These findings reveal a gut microbiota–metabolite–host signalling circuit, in which a microbial metabolite hijacks a core host post-translational modification pathway to promote BC progression, providing novel opportunities for microbiome-targeted diagnosis and therapy. Gut‑microbiota‑derived UDP‑GlcNAc enters circulation, activates host OGT‑mediated O‑GlcNAcylation to stabilize NFIB. This triggers a feed‑forward loop elevating OGT and proto‑oncogene KIT , driving breast tumor progression. Inhibiting OGT blocks this oncogenic axis even with UDP‑GlcNAc‑producing Ruminococcus lactaris . This reveals a gut‑microbe‑metabolite‑host signaling circuit for breast cancer. Download: Download high-res image (170KB) Download: Download full-size image
危险品化学品经营许可证（带存储）