7nl4
From Proteopedia
OsNIP2;1 silicon transporter from rice
Structural highlights
FunctionNIP21_ORYSJ Silicon influx transporter responsible for silicon transport from the external solution to the root cells (PubMed:16572174). Is coupled with the silicon efflux transporter LSI2 in both exodermal and endodermal root cells for an efficient silicon transport across the cells into the stele (PubMed:17625566). Silicon is beneficial to plant growth and helps plants to overcome abiotic and biotic stresses by preventing lodging (falling over) and increasing resistance to pests and diseases, as well as other stresses (PubMed:16572174). Is coupled with LSI2 transporter in roots for efficient uptake of arsenite, which is further dispatched in shoots and grains (PubMed:18626020). Mediates uptake of methylated arsenic species in roots (PubMed:19542298).[1] [2] [3] [4] Publication Abstract from PubMedMany 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. Structural Basis for Silicic Acid Uptake by Higher Plants.,van den Berg B, Pedebos C, Bolla JR, Robinson CV, Basle A, Khalid S J Mol Biol. 2021 Oct 15;433(21):167226. doi: 10.1016/j.jmb.2021.167226. Epub 2021, Sep 3. PMID:34487790[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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