8WOV

Crystal structure of Arabidopsis thaliana UDP-glucose 4-epimerase 2 (AtUGE2) complexed with UDP, G233A mutant

8WOV の概要

• エントリーDOI: 10.2210/pdb8wov/pdb
• 分子名称: UDP-glucose 4-epimerase 2, NICOTINAMIDE-ADENINE-DINUCLEOTIDE, URIDINE-5'-DIPHOSPHATE, ... (4 entities in total)
• 機能のキーワード: isomerase
• 由来する生物種: Arabidopsis thaliana (thale cress)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 83360.69

構造登録者

Matsumoto, M.,Umezawa, A.,Kotake, T.,Fushinobu, S. (登録日: 2023-10-07, 公開日: 2024-05-15, 最終更新日: 2024-07-10)

主引用文献

Umezawa, A.,Matsumoto, M.,Handa, H.,Nakazawa, K.,Miyagawa, M.,Seifert, G.J.,Takahashi, D.,Fushinobu, S.,Kotake, T.
Cytosolic UDP-L-arabinose synthesis by bifunctional UDP-glucose 4-epimerases in Arabidopsis.
Plant J., 119:508-524, 2024

PubMed Abstract: L-Arabinose (L-Ara) is a plant-specific sugar found in cell wall polysaccharides, proteoglycans, glycoproteins, and small glycoconjugates, which play physiologically important roles in cell proliferation and other essential cellular processes. L-Ara is synthesized as UDP-L-arabinose (UDP-L-Ara) from UDP-xylose (UDP-Xyl) by UDP-Xyl 4-epimerases (UXEs), a type of de novo synthesis of L-Ara unique to plants. In Arabidopsis, the Golgi-localized UXE AtMUR4 is the main contributor to UDP-L-Ara synthesis. However, cytosolic bifunctional UDP-glucose 4-epimerases (UGEs) with UXE activity, AtUGE1, and AtUGE3 also catalyze this reaction. For the present study, we first examined the physiological importance of bifunctional UGEs in Arabidopsis. The uge1 and uge3 mutants enhanced the dwarf phenotype of mur4 and further reduced the L-Ara content in cell walls, suggesting that bifunctional UGEs contribute to UDP-L-Ara synthesis. Through the introduction of point mutations exchanging corresponding amino acid residues between AtUGE1 with high UXE activity and AtUGE2 with low UXE activity, two mutations that increase relative UXE activity of AtUGE2 were identified. The crystal structures of AtUGE2 in complex forms with NAD and NAD/UDP revealed that the UDP-binding domain of AtUGE2 has a more closed conformation and smaller sugar-binding site than bacterial and mammalian UGEs, suggesting that plant UGEs have the appropriate size and shape for binding UDP-Xyl and UDP-L-Ara to exhibit UXE activity. The presented results suggest that the capacity for cytosolic synthesis of UDP-L-Ara was acquired by the small sugar-binding site and several mutations of UGEs, enabling diversified utilization of L-Ara in seed plants.

PubMed: 38678521
DOI: 10.1111/tpj.16779

実験手法

X-RAY DIFFRACTION (2.25 Å)