9JUJ

Structure of Arabidopsis thaliana ABCB1 in the inward-facing conformation

Summary for 9JUJ

• Entry DOI: 10.2210/pdb9juj/pdb
• EMDB information: 61827
• Descriptor: ABC transporter B family member 1 (1 entity in total)
• Functional Keywords: abcb1, auxin transport, brassinolide (bl) transport, transport protein
• Biological source: Arabidopsis thaliana (thale cress)
• Total number of polymer chains: 1
• Total formula weight: 145318.95

Authors

Chen, Q.,Su, N.,Guo, J. (deposition date: 2024-10-08, release date: 2025-03-05, Last modification date: 2025-05-14)

Primary citation

Chen, Q.,Zhu, L.,Zhang, S.,Qiao, S.,Ding, Z.J.,Zheng, S.J.,Guo, J.,Su, N.
Structures and mechanisms of the ABC transporter ABCB1 from Arabidopsis thaliana.
Structure, 33:903-915.e5, 2025

PubMed Abstract: The Arabidopsis thaliana auxin transporter ABCB1 plays a fundamental role in the regulation of plant growth and development. While its homolog ABCB19 was previously shown to transport brassinosteroids (BR), another class of essential hormones, the ability of ABCB1 to mediate BR transport has remained unexplored. In this study we show that ABCB1 also transports brassinosteroids with an in vitro brassinolide (BL) transport assay. Using single-particle cryo-electron microscopy, we determined ABCB1 structures in multiple inward-facing conformations in the apo state, ANP-bound state, BL-bound state, and the both BL- and ANP-bound state. BL binds to the large cavity of two transmembrane domains, inducing a slight conformational change. Additionally, we obtained the structure of ABCB1 in an outward-facing conformation. By comparing these different conformations, we elucidated the possible mechanism of hormone transport by ABCB1. These high-resolution structures help us to understand the structural basis for hormone recognition and transport mechanisms of ABCB1.

PubMed: 40101709
DOI: 10.1016/j.str.2025.02.008

Experimental method

ELECTRON MICROSCOPY (3.4 Å)