7BGH image
Entry Detail
PDB ID:
7BGH
Title:
Solution structure of the chloroplast outer envelope channel OEP21
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2021-01-07
Release Date:
2022-01-19
Method Details:
Experimental Method:
Conformers Calculated:
50
Conformers Submitted:
10
Selection Criteria:
structures with the lowest energy
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Outer envelope pore protein 21, chloroplastic
Chain IDs:A
Chain Length:189
Number of Molecules:1
Biological Source:Pisum sativum
Ligand Molecules
Primary Citation
Structural basis of metabolite transport by the chloroplast outer envelope channel OEP21.
Nat.Struct.Mol.Biol. ? ? ? (2023)
PMID: 37156968 DOI: 10.1038/s41594-023-00984-y

Abstact

Triose phosphates (TPs) are the primary products of photosynthetic CO2 fixation in chloroplasts, which need to be exported into the cytosol across the chloroplast inner envelope (IE) and outer envelope (OE) membranes to sustain plant growth. While transport across the IE is well understood, the mode of action of the transporters in the OE remains unclear. Here we present the high-resolution nuclear magnetic resonance (NMR) structure of the outer envelope protein 21 (OEP21) from garden pea, the main exit pore for TPs in C3 plants. OEP21 is a cone-shaped β-barrel pore with a highly positively charged interior that enables binding and translocation of negatively charged metabolites in a competitive manner, up to a size of ~1 kDa. ATP stabilizes the channel and keeps it in an open state. Despite the broad substrate selectivity of OEP21, these results suggest that control of metabolite transport across the OE might be possible.

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