title: Application of a fine thread beam to the structure analysis of a hemihedrally twinned crystal of hydroxylamine oxidoreductase.
abstract: Accurate diffraction intensity data have been collected from a twinned P6(3) crystal of the 24-haem protein hydroxylamine oxidoreductase, from a nitrifying chemoautotrophic bacterium Nitrosomonas europaea, using synchrotron radiation at station BL6A of the Photon Factory. Estimation of the twinning fraction and deconvoluted intensity data, including native and heavy-atom derivative data, gave an improved Patterson function. Four diffraction data sets were collected from one crystal and an estimation of the twinning fraction to confirm the phenomena was undertaken. The successfully detwinned data sets were utilized in the structure analysis of the present enzyme. The mechanism of twinned-crystal formation is also discussed.
authors.affiliation: Department of Life Science, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Igarashi
authors.forename: H
authors.initials: H
authors.lastname: Moriyama
authors.forename: N
authors.initials: N
authors.lastname: Tanaka