title: High-Quality Protein Crystal Growth of Mouse Lipocalin-Type Prostaglandin D Synthase in Microgravity.
abstract: Lipocalin-type prostaglandin (PG) D synthase (L-PGDS) catalyzes the isomerization of PGH(2) to PGD(2) and is involved in the regulation of pain and of nonrapid eye movement sleep and the differentiation of male genital organs and adipocytes, etc. L-PGDS is secreted into various body fluids and binds various lipophilic compounds with high affinities, acting also as an extracellular transporter. Mouse L-PGDS with a C65A mutation was previously crystallized with citrate or malonate as a precipitant, and the X-ray crystallographic structure was determined at 2.0 Å resolution. To obtain high-quality crystals, we tried, unsuccessfully, to crystallize the C65A mutant in microgravity under the same conditions used in the previous study. After further purifying the protein and changing the precipitant to polyethylene glycol (PEG) 8000, high-quality crystals were grown in microgravity. The precipitant solution was 40% (w/v) PEG 8000, 100 mM sodium chloride, and 100 mM HEPES-NaOH (pH 7.0). Crystals grew on board the International Space Station for 11 weeks in 2007, yielding single crystals of the wild-type L-PGDS and the C65A mutant, both of which diffracted at around 1.0 Å resolution. The crystal quality was markedly improved through the use of a high-viscosity precipitant solution in microgravity, in combination with the use of a highly purified protein.
authors.affiliation: Maruwa Foods and Biosciences Inc. , 170-1 Tsutsui-cho, Yamatokoriyama, Nara 639-1123, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Inaka
authors.forename: Sachiko
authors.initials: S
authors.lastname: Takahashi
authors.forename: Kosuke
authors.initials: K
authors.lastname: Aritake
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Tsurumura
authors.forename: Naoki
authors.initials: N
authors.lastname: Furubayashi
authors.forename: Bin
authors.initials: B
authors.lastname: Yan
authors.forename: Erika
authors.initials: E
authors.lastname: Hirota
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sano
authors.forename: Masaru
authors.initials: M
authors.lastname: Sato
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Yoshimura
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Urade