Nature Communications, 20 February, 2025, DOI：https://doi.org/10.1038/s41467-025-56943-2

Structural basis of urea transport by Arabidopsis thaliana DUR3

Weidong An, Yiwei Gao, Laihua Liu, Qinru Bai, Jun Zhao, Yan Zhao & Xuejun C. Zhang

Abstract

Urea is a primary nitrogen source used as fertilizer in agricultural plant production and a crucial nitrogen metabolite in plants, playing an essential role in modern agriculture. In plants, DUR3 is a proton-driven high-affinity urea transporter located on the plasma membrane. It not only absorbs external low-concentration urea as a nutrient but also facilitates nitrogen transfer by recovering urea from senescent leaves. Despite its importance, the high-affinity urea transport mechanism in plants remains insufficiently understood. In this study, we determine the structures of Arabidopsis thaliana DUR3 in two different conformations: the inward-facing open state of the apo structure and the occluded urea-bound state, with overall resolutions of 2.8 Å and 3.0 Å, respectively. By comparing these structures and analyzing their functional characteristics, we elucidated how urea molecules are specifically recognized. In the urea-bound structure, we identified key titratable amino acid residues and proposed a model for proton involvement in urea transport based on structural and functional data. This study enhances our understanding of proton-driven urea transport mechanisms in DUR3.

Article link：https://www.nature.com/articles/s41467-025-56943-2