Structural Basis for Silicic Acid Uptake by Higher Plants

JOURNAL OF MOLECULAR BIOLOGY

卷:433

Article

van den Berg, Bert¹  Pedebos, Conrado²  Bolla, Jani R.^3,4  Robinson, Carol V.^3,4  Basle, Arnaud¹  Khalid, Syma^2,5 

[1] Newcastle Univ, Biosci Inst, Sch Med, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England

[2] Univ Southampton, Sch Chem, Southampton SO17 1BJ, Hants, England

[3] Univ Oxford, Phys & Theoret Chem Lab, Oxford OX1 3QZ, England

[4] Kavli Inst Nanosci Discovery, South Parks Rd, Oxford OX1 3QU, England

[5] Univ Oxford, Dept Biochem, Oxford OX1 3QU, England

关键词: silicic acid transport;    NIP channel;    aquaporin;    X-ray crystal structure;    molecular dynamics;   

DOI  :  10.1016/j.jmb.2021.167226

来源: Elsevier

【 摘 要 】

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. (C) 2021 The Authors. Published by Elsevier Ltd.

【 授权许可】

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