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Title: ANS complex of St John's wort PR-10 protein with 28 copies in the asymmetric unit: A fiendish combination of pseudosymmetry with tetartohedral twinning

Hyp-1, a pathogenesis-related class 10 (PR-10) protein from St John's wort (Hypericum perforatum), was crystallized in complex with the fluorescent probe 8-anilino-1-naphthalene sulfonate (ANS). The highly pseudosymmetric crystal has 28 unique protein molecules arranged in columns with sevenfold translational noncrystallographic symmetry (tNCS) along c and modulated X-ray diffraction with intensity crests at l = 7n and l = 7n ± 3. The translational NCS is combined with pseudotetragonal rotational NCS. The crystal was a perfect tetartohedral twin, although detection of twinning was severely hindered by the pseudosymmetry. The structure determined at 2.4 Å resolution reveals that the Hyp-1 molecules (packed as β-sheet dimers) have three novel ligand-binding sites (two internal and one in a surface pocket), which was confirmed by solution studies. In addition to 60 Hyp-1-docked ligands, there are 29 interstitial ANS molecules distributed in a pattern that violates the arrangement of the protein molecules and is likely to be the generator of the structural modulation. In particular, whenever the stacked Hyp-1 molecules are found closer together there is an ANS molecule bridging them.
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5]
  1. Polish Academy of Sciences, Poznan (Poland). Center for Biocrystallogrphic Research.
  2. Argonne National Lab., Argonne, IL (United States). Synchrotron Radiation Research Section.
  3. Poznan Univ. of Medical Sciecnes, Poznan (Poland). Dept. of Organic Chemistry.
  4. Univ. of Cambridge, Cambridge (England). Dept. of Haematology.
  5. Polish Academy of Sciences, Poznan (Poland). Center for Biocrystallogrphic Research; A. Mickiewicz Univ., Poznan (Poland). Dept. of Crystallography.
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Acta Crystallographica. Section D: Biological Crystallography (Online)
Additional Journal Information:
Journal Name: Acta Crystallographica. Section D: Biological Crystallography (Online); Journal Volume: 71; Journal Issue: 4; Journal ID: ISSN 1399-0047
International Union of Crystallography
Research Org:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Org:
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES pathogenesis-related class 10 protein; St John’s wort; Hypericum perforatum; 8-anilino-1-naphthalene sulfonate