title: Binding of the plant hormone kinetin in the active site of Mistletoe Lectin I from Viscum album.
abstract: The crystal structure of the ribosome inhibiting protein Mistletoe Lectin I (ML-I) derived from the European mistletoe, Viscum album, in complex with kinetin has been refined at 2.7Å resolution. Suitably large crystals of ML-I were obtained applying the counter diffusion method using the Gel Tube R Crystallization Kit (GT-R) on board the Russian Service Module on the international space station ISS within the GCF mission No. 6, arranged by the Japanese aerospace exploration agency (JAXA). Hexagonal bi-pyramidal crystals were grown during three months under microgravity. Before data collection the crystals were soaked in a saturated solution of kinetin and diffraction data to 2.7Å were collected using synchrotron radiation and cryogenic techniques. The atomic model was refined and revealed a single kinetin molecule in the ribosome inactivation site of ML-I. The complex demonstrates the feasibility of mistletoe to bind plant hormones out of the host regulation system as part of a self protection mechanism.
authors: Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.
authors: Piotr H
authors: PH
authors: Małecki
authors: Wojciech
authors: W
authors: Rypniewski
authors: Maciej
authors: M
authors: Szymański
authors: Jan
authors: J
authors: Barciszewski
authors: Arne
authors: A
authors: Meyer
mesh_terms: D020134:Catalytic Domain; D003460:Crystallization / Q000379:methods; D018360:Crystallography, X-Ray; D007701:Kinetin / Q000737:chemistry*; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry; D010937:Plant Growth Regulators / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D054790:Ribosome Inactivating Proteins, Type 2 / Q000737:chemistry*; D014118:Toxins, Biological / Q000737:chemistry*; D028182:Viscum album / Q000378:metabolism*; D014893:Weightlessness
chemical_list: D046912:Multiprotein Complexes; D010937:Plant Growth Regulators; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C488862:mistletoe lectin I; D007701:Kinetin