title: Leaf-specific pathogenesis-related 10 homolog, PgPR-10.3, shows in silico binding affinity with several biologically important molecules.
abstract: BACKGROUND
  Pathogenesis-related 10 (PR-10) proteins are small, cytosolic proteins with a similar three-dimensional structure. Crystal structures for several PR-10 homologs have similar overall folding patterns, with an unusually large internal cavity that is a binding site for biologically important molecules. Although structural information on PR-10 proteins is substantial, understanding of their biological function remains limited. Here, we showed that one of the PgPR-10 homologs, PgPR-10.3, shares binding properties with flavonoids, kinetin, emodin, deoxycholic acid, and ginsenoside Re (1 of the steroid glycosides).
  
  
  METHODS
  Gene expression patterns of PgPR-10.3 were analyzed by quantitative real-time PCR. The three-dimensional structure of PgPR-10 proteins was visualized by homology modeling, and docking to retrieve biologically active molecules was performed using AutoDock4 program.
  
  
  RESULTS
  Transcript levels of PgPR-10.3 expressed in leaves, stems, and roots of 3-wk-old ginseng plantlets were on average 86-fold lower than those of PgPR-10.2. In mature 2-yr-old ginseng plants, the mRNA of PgPR-10.3 is restricted to leaves. Ginsenoside Re production is especially prominent in leaves of Panax ginseng Meyer, and the binding property of PgPR-10.3 with ginsenoside Re suggests that this protein has an important role in the control of secondary metabolism.
  
  
  CONCLUSIONS
  Although ginseng PR-10.3 gene is expressed in all organs of 3-wk-old plantlets, its expression is restricted to leaves in mature 2-yr-old ginseng plants. The putative binding property of PgPR-10.3 with Re is intriguing. Further verification of binding affinity with other biologically important molecules in the large hydrophobic cavity of PgPR-10.3 may provide an insight into the biological features of PR-10 proteins.
authors: Department of Plant Biotechnology, College of Agriculture and Life Science, Chonnam National University, Gwangju, Korea.
authors: Jin Haeng
authors: JH
authors: Han
authors: Department of Plant Biotechnology, College of Agriculture and Life Science, Chonnam National University, Gwangju, Korea.
authors: Jin Hee
authors: JH
authors: Lee
authors: Department of Plant Biotechnology, College of Agriculture and Life Science, Chonnam National University, Gwangju, Korea.
authors: Ok Ran
authors: OR
authors: Lee
keywords: Panax ginseng Meyer; abiotic stress; ligand binding; pathogenesis-related-10; salicylic acid