title: Structure of mistletoe lectin I from Viscum album in complex with the phytohormone zeatin.
abstract: The crystal structure of mistletoe lectin I (ML-I) isolated from the European mistletoe Viscum album in complex with the most active phytohormone zeatin has been analyzed and refined to 2.54 A resolution. X-ray suitable crystals of ML-I were obtained by the counter-diffusion method using the Gel-Tube R crystallization kit (GT-R) onboard the Russian Service Module on the international space station ISS. High quality hexagonal bipyramidal crystals were grown during 3 months under microgravity conditions. Selected crystals were soaked in a saturated solution of zeatin and subsequently diffraction data were collected applying synchrotron radiation. A distinct F(o)-F(c) electron density has been found inside a binding pocket located in subunit B of ML-I and has been interpreted as a single zeatin molecule. The structure was refined to investigate the zeatin-ML-I interactions in detail. The results demonstrate the ability of mistletoe to protect itself from the host transpiration regulation by absorbing the most active host plant hormones as part of a defense mechanism.
authors: Institute of Biochemistry and Molecular Biology, University of Hamburg, c/o DESY, Notkestr. 85, Building 22a, 22603 Hamburg, Germany.
authors: Arne
authors: A
authors: Meyer
authors: Wojciech
authors: W
authors: Rypniewski
authors: Maciej
authors: M
authors: Szymański
authors: Wolfgang
authors: W
authors: Voelter
authors: Jan
authors: J
authors: Barciszewski
authors: Christian
authors: C
authors: Betzel
mesh_terms: D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D008954:Models, Biological; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry; D010937:Plant Growth Regulators / Q000378:metabolism; D011485:Protein Binding; D054790:Ribosome Inactivating Proteins, Type 2 / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D014118:Toxins, Biological / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D028182:Viscum album / Q000737:chemistry*; D015026:Zeatin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D046912:Multiprotein Complexes; D010937:Plant Growth Regulators; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C488862:mistletoe lectin I; D015026:Zeatin