8vgb
Crystal Structure of Guanine Nucleotide-Binding Protein Alpha Subunit (G Protein) from Oryza sativa in complex with GDP
Structural highlights
FunctionGPA1_ORYSI Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. May function in a signal transduction pathway required for normal growth and development of internodes, leaves, panicles and seeds. Involved in gibberellin signal transduction. Involved in R gene-mediated disease resistance. Functions upstream of the small GTPase RAC1 in the early steps of signaling. Involved in brassinosteroid response. May not be a signaling molecule in BRI1-mediated perception or transduction.[UniProtKB:Q0DJ33] Publication Abstract from PubMedHeterotrimeric GTP-binding protein alpha subunit (Galpha) and its cognate regulator of G-protein signaling (RGS) protein transduce signals in eukaryotes spanning protists, amoeba, animals, fungi, and plants. The core catalytic mechanisms of the GTPase activity of Galpha and the interaction interface with RGS for the acceleration of GTP hydrolysis seem to be conserved across these groups; however, the RGS gene is under low selective pressure in plants, resulting in its frequent loss. Our current understanding of the structural basis of Galpha:RGS regulation in plants has been shaped by Arabidopsis Galpha, (AtGPA1), which has a cognate RGS protein. To gain a comprehensive understanding of this regulation beyond Arabidopsis, we obtained the x-ray crystal structures of Oryza sativa Galpha, which has no RGS, and Selaginella moellendorffi (a lycophyte) Galpha that has low sequence similarity with AtGPA1 but has an RGS. We show that the three-dimensional structure, protein-protein interaction with RGS, and the dynamic features of these Galpha are similar to AtGPA1 and metazoan Galpha. Molecular dynamic simulation of the Galpha-RGS interaction identifies the contacts established by specific residues of the switch regions of GTP-bound Galpha, crucial for this interaction, but finds no significant difference due to specific amino acid substitutions. Together, our data provide valuable insights into the regulatory mechanisms of plant G-proteins but do not support the hypothesis of adaptive co-evolution of Galpha:RGS proteins in plants. Structure-function analysis of plant G-protein regulatory mechanisms identifies key Galpha-RGS protein interactions.,Torres-Rodriguez MD, Lee SG, Roy Choudhury S, Paul R, Selvam B, Shukla D, Jez JM, Pandey S J Biol Chem. 2024 May;300(5):107252. doi: 10.1016/j.jbc.2024.107252. Epub 2024 , Apr 1. PMID:38569936[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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