Department of Biotechnology, The University of Tokyo, Tokyo, 113-8657, Japan; Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, 113-8657, Japan.
Curr Opin Chem Biol. 2021 Apr;61:53-62. doi: 10.1016/j.cbpa.2020.09.007. Epub 2020 Nov 7.
UDP-glucose 4-epimerase (GalE) catalyzes the interconversion of UDP-glucose (UDP-Glc) and UDP-galactose (UDP-Gal) and/or the interconversion of UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylgalactosamine (UDP-GalNAc) in sugar metabolism. GalEs belong to the short-chain dehydrogenase/reductase superfamily, use a conserved 'transient keto intermediate' mechanism and have variable substrate specificity. GalEs have been classified into three groups based on substrate specificity: group 1 prefers UDP-Glc/Gal, group 3 prefers UDP-GlcNAc/GalNAc, and group 2 has comparable activities for both types of the substrates. The phylogenetic relationship and structural basis for the specificities of GalEs revealed possible molecular evolution of UDP-hexose 4-epimerases in various organisms. Based on the recent advances in studies on GalEs and related enzymes, an updated view of their evolutional diversification is presented.
UDP-葡萄糖 4-差向异构酶（GalE）催化 UDP-葡萄糖（UDP-Glc）和 UDP-半乳糖（UDP-Gal）之间的相互转化，以及/或者 UDP-N-乙酰葡萄糖胺（UDP-GlcNAc）和 UDP-N-乙酰半乳糖胺（UDP-GalNAc）之间的相互转化，在糖代谢中。GalE 属于短链脱氢酶/还原酶超家族，使用保守的“瞬态酮中间物”机制，具有可变的底物特异性。根据底物特异性，GalE 分为三组：第 1 组优先选择 UDP-Glc/Gal，第 3 组优先选择 UDP-GlcNAc/GalNAc，第 2 组对这两种底物的活性相当。GalE 的系统发育关系和结构基础揭示了各种生物体中 UDP-己糖 4-差向异构酶的可能分子进化。基于 GalE 和相关酶的研究进展，提出了它们进化多样化的最新观点。
Zotero 插件