School of Biological and Food Processing Engineering, Huanghuai University, Zhumadian 463000, China.
Institute of Agricultural Products Fermentation Engineering and Application, Huanghuai University, Zhumadian 463000, China.
Molecules. 2022 Aug 20;27(16):5315. doi: 10.3390/molecules27165315.
Rhamnose-associated molecules are attracting attention because they are present in bacteria but not mammals, making them potentially useful as antibacterial agents. Additionally, they are also valuable for tumor immunotherapy. Thus, studies on the functions and biosynthetic pathways of rhamnose-containing compounds are in progress. In this paper, studies on the biosynthetic pathways of three rhamnose donors, i.e., deoxythymidinediphosphate-L-rhamnose (dTDP-Rha), uridine diphosphate-rhamnose (UDP-Rha), and guanosine diphosphate rhamnose (GDP-Rha), are firstly reviewed, together with the functions and crystal structures of those associated enzymes. Among them, dTDP-Rha is the most common rhamnose donor, and four enzymes, including glucose-1-phosphate thymidylyltransferase RmlA, dTDP-Glc-4,6-dehydratase RmlB, dTDP-4-keto-6-deoxy-Glc-3,5-epimerase RmlC, and dTDP-4-keto-Rha reductase RmlD, are involved in its biosynthesis. Secondly, several known rhamnosyltransferases from , , , , and are discussed. In these studies, however, the functions of rhamnosyltransferases were verified by employing gene knockout and radiolabeled substrates, which were almost impossible to obtain and characterize the products of enzymatic reactions. Finally, the application of rhamnose-containing compounds in disease treatments is briefly described.
鼠李糖相关分子因其存在于细菌中而不存在于哺乳动物中而受到关注，这使它们有可能成为有用的抗菌剂。此外，它们在肿瘤免疫治疗中也很有价值。因此，目前正在研究含鼠李糖化合物的功能和生物合成途径。本文首先综述了三种鼠李糖供体（即脱氧胸苷二磷酸-L-鼠李糖（dTDP-Rha）、尿苷二磷酸-鼠李糖（UDP-Rha）和鸟苷二磷酸鼠李糖（GDP-Rha））的生物合成途径，以及相关酶的功能和晶体结构。其中，dTDP-Rha 是最常见的鼠李糖供体，其生物合成涉及四种酶，包括葡萄糖-1-磷酸胸苷基转移酶 RmlA、dTDP-Glc-4,6-脱水酶 RmlB、dTDP-4-酮-6-脱氧-Glc-3,5-差向异构酶 RmlC 和 dTDP-4-酮-Rha 还原酶 RmlD。其次，讨论了来自、、、和的几种已知的鼠李糖基转移酶。然而，在这些研究中，通过基因敲除和放射性标记底物来验证鼠李糖基转移酶的功能，这几乎不可能获得和表征酶促反应的产物。最后，简要描述了含鼠李糖化合物在疾病治疗中的应用。
