8tg0
From Proteopedia
Solution NMR structure of the cold shock domain of the Arabidopsis thaliana glycine-rich protein AtGRP2
Structural highlights
FunctionCSP2_ARATH Chaperone that binds to RNA, single- (ssDNA) and double-stranded (dsDNA) DNA, and unwinds nucleic acid duplex. Accelerates seed germination and seedling growth under cold stress, and contributes to enhancement of cold and freezing tolerance. Regulates flowering transition, and flower and seed development. Promotes seed germination under salt stress. May regulate respiratory oxygen uptake.[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedAtGRP2 is a glycine-rich, RNA-binding protein that plays pivotal roles in abiotic stress response and flowering time regulation in Arabidopsis thaliana. AtGRP2 consists of an N-terminal cold shock domain (CSD) and two C-terminal CCHC-type zinc knuckles interspersed with glycine-rich regions. Here, we investigated the structure, dynamics, and nucleic acid binding properties of AtGRP2-CSD. The 2D [(1)H,(15)N] HSQC spectrum of AtGRP2-CSD(1-79) revealed the presence of a partially folded intermediate in equilibrium with the folded state. The addition of eleven residues at the C-terminus stabilized the folded conformation. The three-dimensional structure of AtGRP2-CSD(1-90) unveiled a beta-barrel composed of five antiparallel beta-strands and a 3(10) helical turn, along with an ordered C-terminal extension, a conserved feature in eukaryotic CSDs. Direct contacts between the C-terminal extension and the beta3-beta4 loop further stabilized the CSD fold. AtGRP2-CSD(1-90) exhibited nucleic acid binding via solvent-exposed residues on strands beta2 and beta3, as well as the beta3-beta4 loop, with higher affinity for DNA over RNA, particularly favoring pyrimidine-rich sequences. Furthermore, DNA binding induced rigidity in the beta3-beta4 loop, evidenced by (15)N-(1)H NOE values. Mutation of residues W17, F26, and F37, in the central beta-sheet, completely abolished DNA binding, highlighting the significance of pi-stacking interactions in the binding mechanism. These results shed light on the mechanism of nucleic acid recognition employed by AtGRP2, creating a framework for the development of biotechnological strategies aimed at enhancing plant resistance to abiotic stresses. Structural basis of nucleic acid recognition by the N-terminal cold shock domain of the plant glycine-rich protein AtGRP2.,Pougy KC, Moraes BS, Malizia-Motta CLF, Lima LMTR, Sachetto-Martins G, Almeida FCL, Pinheiro AS J Biol Chem. 2024 Oct 17:107903. doi: 10.1016/j.jbc.2024.107903. PMID:39426727[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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