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.
abstract: 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.
authors: Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.
authors: Joanna
authors: J
authors: Sliwiak
authors: Synchrotron Radiation Research Section, National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439, USA.
authors: Zbigniew
authors: Z
authors: Dauter
authors: Department of Organic Chemistry, Poznan University of Medical Sciences, Poznan, Poland.
authors: Marcin
authors: M
authors: Kowiel
authors: Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England.
authors: Airlie J
authors: AJ
authors: McCoy
authors: Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England.
authors: Randy J
authors: RJ
authors: Read
authors: Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.
authors: Mariusz
authors: M
authors: Jaskolski
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D020902:Hypericum / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation
chemical_list: C515594:8-anilino-1-naphthalenesulfonic acid; D000817:Anilino Naphthalenesulfonates; D010940:Plant Proteins
keywords: 8-anilino-1-naphthalene sulfonate; Hypericum perforatum; St John's wort; pathogenesis-related class 10 protein