9LVB

IAA-free AUX1

Summary for 9LVB

• Entry DOI: 10.2210/pdb9lvb/pdb
• EMDB information: 63418
• Descriptor: Auxin transporter protein 1,Soluble cytochrome b562, heavy chain, light chain, ... (4 entities in total)
• Functional Keywords: leut-fold, transport, protein transport/immune system, protein transport-immune system complex
• Biological source: Arabidopsis thaliana (thale cress); More
• Total number of polymer chains: 4
• Total formula weight: 141273.63

Authors

Jing, D.,Kong, F.,Wang, C.C.,Shi, Y.G.,Huang, G.X.Y. (deposition date: 2025-02-12, release date: 2025-07-23, Last modification date: 2025-09-10)

Primary citation

Jing, D.,Kong, F.,Lu, X.,Huang, G.,Huang, J.,Wang, H.,Shi, Y.,Wang, C.
Structural basis of auxin binding and transport by Arabidopsis thaliana AUX1.
Proc.Natl.Acad.Sci.USA, 122:e2513424122-e2513424122, 2025

PubMed Abstract: Indole-3-acetic acid (IAA), the major form of auxin, is essential for plant growth. Auxin resistant 1 (AUX1), the first identified auxin importer, plays a crucial role in polar auxin transport (PAT). Here, we present cryo-EM structures of AUX1 in the IAA-free and IAA-bound states. AUX1 exists as a monomer that contains 11 transmembrane helices (TMs). TMs 1 to 5 and 6 to 10 constitute the two halves of a classic LeuT-fold, and TM11 interacts with both halves at the interface. In the IAA-bound state, IAA is specifically recognized in a central pocket formed by TM1, TM3, TM6, and TM8. In the presence of IAA, TM1 and TM6 undergo marked conformational changes that are critical for IAA transport. His249 stands out to be a key residue for substrate uptake and release. Our structures reveal the molecular basis for AUX1-mediated IAA binding and transport.

PubMed: 40720658
DOI: 10.1073/pnas.2513424122

Experimental method

ELECTRON MICROSCOPY (3.97 Å)