7NL4 image
Entry Detail
PDB ID:
7NL4
Title:
OsNIP2;1 silicon transporter from rice
Biological Source:
PDB Version:
Deposition Date:
2021-02-22
Release Date:
2021-11-03
Method Details:
Experimental Method:
Resolution:
3.00 Å
R-Value Free:
0.28
R-Value Work:
0.23
R-Value Observed:
0.24
Space Group:
P 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Aquaporin NIP2-1
Chain IDs:A, B, C, D, E, F, G, H
Chain Length:227
Number of Molecules:8
Biological Source:Oryza sativa subsp. japonica
Ligand Molecules
Primary Citation
Structural Basis for Silicic Acid Uptake by Higher Plants.
J.Mol.Biol. 433 167226 167226 (2021)
PMID: 34487790 DOI: 10.1016/j.jmb.2021.167226

Abstact

Many of the world's most important food crops such as rice, barley and maize accumulate silicon (Si) to high levels, resulting in better plant growth and crop yields. The first step in Si accumulation is the uptake of silicic acid by the roots, a process mediated by the structurally uncharacterised NIP subfamily of aquaporins, also named metalloid porins. Here, we present the X-ray crystal structure of the archetypal NIP family member from Oryza sativa (OsNIP2;1). The OsNIP2;1 channel is closed in the crystal structure by the cytoplasmic loop D, which is known to regulate channel opening in classical plant aquaporins. The structure further reveals a novel, five-residue extracellular selectivity filter with a large diameter. Unbiased molecular dynamics simulations show a rapid opening of the channel and visualise how silicic acid interacts with the selectivity filter prior to transmembrane diffusion. Our results will enable detailed structure-function studies of metalloid porins, including the basis of their substrate selectivity.

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Primary Citation of related structures