title: JAXA protein crystallization in space: ongoing improvements for growing high-quality crystals.
abstract: The Japan Aerospace Exploration Agency (JAXA) started a high-quality protein crystal growth project, now called JAXA PCG, on the International Space Station (ISS) in 2002. Using the counter-diffusion technique, 14 sessions of experiments have been performed as of 2012 with 580 proteins crystallized in total. Over the course of these experiments, a user-friendly interface framework for high accessibility has been constructed and crystallization techniques improved; devices to maximize the use of the microgravity environment have been designed, resulting in some high-resolution crystal growth. If crystallization conditions were carefully fixed in ground-based experiments, high-quality protein crystals grew in microgravity in many experiments on the ISS, especially when a highly homogeneous protein sample and a viscous crystallization solution were employed. In this article, the current status of JAXA PCG is discussed, and a rational approach to high-quality protein crystal growth in microgravity based on numerical analyses is explained.
authors.affiliation: Confocal Science Inc., Hayakawa 2nd Building 7F, 2-12-2 Iwamoto-cho, Chiyoda-ku, Tokyo 101-0032, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Takahashi
authors.forename: Kazunori
authors.initials: K
authors.lastname: Ohta
authors.forename: Naoki
authors.initials: N
authors.lastname: Furubayashi
authors.forename: Bin
authors.initials: B
authors.lastname: Yan
authors.forename: Misako
authors.initials: M
authors.lastname: Koga
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Wada
authors.forename: Mitsugu
authors.initials: M
authors.lastname: Yamada
authors.forename: Koji
authors.initials: K
authors.lastname: Inaka
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyoshi
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kamigaichi
mesh_terms: D003460:Crystallization; D007564:Japan; D011506:Proteins / Q000737:chemistry*; D013026:Space Flight
chemical_list: D011506:Proteins
keywords: JAXA; Japan Experiment Module `Kibo'; counter-diffusion; impurity depletion zone; microgravity; protein crystal; protein depletion zone