8HIW | pdb_00008hiw

AtALMT9 in the apo state

• PDB DOI: https://doi.org/10.2210/pdb8HIW/pdb
• EM Map EMD-34828: EMDB EMDataResource

• Classification: TRANSPORT PROTEIN
• Organism(s): Arabidopsis thaliana
• Expression System: Spodoptera frugiperda
• Mutation(s): No 
• Membrane Protein: Yes  PDBTM


• Deposited: 2022-11-22 Released: 2024-03-06 
• Deposition Author(s): Gong, D.S.
• Funding Organization(s): National Natural Science Foundation of China (NSFC)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.34 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Literature

Structural insight into the Arabidopsis vacuolar anion channel ALMT9 shows clade specificity.

Qian, D., Chai, Y., Li, W., Cui, B., Lin, S., Wang, Z., Wang, C., Qu, L.Q., Gong, D.

(2024) Cell Rep 43: 114731-114731

• PubMed: 39269901 
• DOI: https://doi.org/10.1016/j.celrep.2024.114731
• Primary Citation Related Structures: 
  8HIW, 8HIY, 8ZVF


• PubMed Abstract: 
  

  The Arabidopsis thaliana aluminum-activated malate transporter 9 (AtALMT9) functions as a vacuolar chloride channel that regulates the stomatal aperture. Here, we present the cryoelectron microscopy (cryo-EM) structures of AtALMT9 in three distinct states. AtALMT9 forms a dimer, and the pore is lined with four positively charged rings. The apo-AtALMT9 state shows a putative endogenous citrate obstructing the pore, where two W120 constriction residues enclose a gate with a pore radius of approximately 1.8 Å, representing an open state. Interestingly, channel closure is solely controlled by W120. Compared to wild-type plants, the W120A mutant exhibits more sensitivity to drought stress and is unable to restore the visual phenotype on leaves upon water recovery, reflecting persistent stomatal opening. Furthermore, notable variations are noted in channel gating and substrate recognition of Glycine max ALMT12, AtALMT9, and AtALMT1. In summary, our investigation enhances comprehension of the interplay between structure and function within the ALMT family.

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Organizational Affiliation: 
• State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China. Electronic address: [e-mail].
Key Laboratory of Plant Molecular Physiology, Institute of Botany, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100093, China; College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China.
School of Basic Medicine and Clinical Pharmacy and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China.
Faculty of Pharmaceutical Sciences, Shenzhen University of Advanced Technology, Shenzhen 581055, China.
Faculty of Pharmaceutical Sciences, Shenzhen University of Advanced Technology, Shenzhen 581055, China. Electronic address: [e-mail].
Key Laboratory of Plant Molecular Physiology, Institute of Botany, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100093, China; College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: [e-mail].
State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China. Electronic address: [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: 134.43 kDa 
• Atom Count: 5,945 
• Modeled Residue Count: 768 
• Deposited Residue Count: 1,196 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Aluminum-activated malate transporter 9	A, B	598	Arabidopsis thaliana	Mutation(s): 0  Gene Names: ALMT9, At3g18440, MYF24.16 Membrane Entity: Yes
UniProt
Find proteins for Q9LS46 (Arabidopsis thaliana) Explore Q9LS46  Go to UniProtKB:  Q9LS46

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CIT (Subject of Investigation/LOI)	C [auth B]	CITRIC ACID C6 H8 O7 KRKNYBCHXYNGOX-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.34 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2024-03-06 
Deposition Author(s): Gong, D.S.

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Funding Organization	Location	Grant Number
National Natural Science Foundation of China (NSFC)	China	32271254

Revision History  

• Version 1.0: 2024-03-06
  Type: Initial release
  
• Version 1.1: 2024-09-25
  Changes: Data collection, Database references