8TEL | pdb_00008tel

Cryo-EM structure of Arabidopsis thaliana Bor1 mutant (R637E/E641R/R643E) in the occluded conformation in lauryl maltose neopentyl glycol (LMNG)

• PDB DOI: https://doi.org/10.2210/pdb8TEL/pdb
• EM Map EMD-41190: EMDB EMDataResource

• Classification: TRANSPORT PROTEIN
• Organism(s): Arabidopsis thaliana
• Expression System: Saccharomyces cerevisiae
• Mutation(s): Yes 
• Membrane Protein: Yes  PDBTM


• Deposited: 2023-07-06 Released: 2024-07-10 
• Deposition Author(s): Jiang, Y., Jiang, J.
• Funding Organization(s): National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)

---

Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 2.77 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

The Bor1 elevator transport cycle is subject to autoinhibition and activation.

Jiang, Y., Jiang, J.

(2024) Nat Commun 15: 9090-9090

• PubMed: 39433547 
• DOI: https://doi.org/10.1038/s41467-024-53411-1
• Primary Citation Related Structures: 
  8TEG, 8TEH, 8TEI, 8TEJ, 8TEL, 8TEM, 8TEN


• PubMed Abstract: 
  

  Boron, essential for plant growth, necessitates precise regulation due to its potential toxicity. This regulation is achieved by borate transporters (BORs), which are homologous to the SLC4 family. The Arabidopsis thaliana Bor1 (AtBor1) transporter from clade I undergoes slow regulation through degradation and translational suppression, but its potential for fast regulation via direct activity modulation was unclear. Here, we combine cryo-electron microscopy, mutagenesis, and functional characterization to study AtBor1, revealing high-resolution structures of the dimer in one inactive and three active states. Our findings show that AtBor1 is regulated by two distinct mechanisms: an autoinhibitory domain at the carboxyl terminus obstructs the substrate pathway via conserved salt bridges, and phosphorylation of Thr410 allows interaction with a positively charged pocket at the cytosolic face, essential for borate transport. These results elucidate the molecular basis of AtBor1's activity regulation and highlight its role in fast boron level regulation in plants.

---

Organizational Affiliation: 
• Laboratory of Membrane Proteins and Structural Biology, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA. [e-mail].
Transporter Biology Group, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia. [e-mail].
Laboratory of Membrane Proteins and Structural Biology, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA. [e-mail].

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: electron microscopy

Macromolecule Content 

• Total Structure Weight: 160.22 kDa 
• Atom Count: 7,806 
• Modeled Residue Count: 988 
• Deposited Residue Count: 1,428 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Boron transporter 1	A, B	714	Arabidopsis thaliana	Mutation(s): 3  Gene Names: BOR1, At2g47160, T3D7.3 Membrane Entity: Yes
UniProt
Find proteins for Q8VYR7 (Arabidopsis thaliana) Explore Q8VYR7  Go to UniProtKB:  Q8VYR7

Small Molecules

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
TPO	A, B	L-PEPTIDE LINKING	C4 H10 N O6 P		THR

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 2.77 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
MODEL REFINEMENT	PHENIX
RECONSTRUCTION	RELION

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2024-07-10 
Deposition Author(s): Jiang, Y., Jiang, J.

---

Funding Organization	Location	Grant Number
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)	United States	--

Revision History  

• Version 1.0: 2024-07-10
  Type: Initial release
  
• Version 1.1: 2024-10-23
  Changes: Data collection, Structure summary
• Version 1.2: 2025-01-22
  Changes: Data collection, Database references