title: Biochemical and structural characterization of an endoplasmic reticulum-localized late embryogenesis abundant (LEA) protein from the liverwort Marchantia polymorpha.
abstract: Late embryogenesis abundant (LEA) proteins, which accumulate to high levels in seeds during late maturation, are associated with desiccation tolerance. A member of the LEA protein family was found in cultured cells of the liverwort Marchantia polymorpha; preculture treatment of these cells with 0.5M sucrose medium led to their acquisition of desiccation tolerance. We characterized this preculture-induced LEA protein, designated as MpLEA1. MpLEA1 is predominantly hydrophilic with a few hydrophobic residues that may represent its putative signal peptide. The protein also contains a putative endoplasmic reticulum (ER) retention sequence, HEEL, at the C-terminus. Microscopic observations indicated that GFP-fused MpLEA1 was mainly localized in the ER. The recombinant protein MpLEA1 is intrinsically disordered in solution. On drying, MpLEA1 shifted predominantly toward α-helices from random coils. Such changes in conformation are a typical feature of the group 3 LEA proteins. Recombinant MpLEA1 prevented the aggregation of α-casein during desiccation-rehydration events, suggesting that MpLEA1 exerts anti-aggregation activity against desiccation-sensitive proteins by functioning as a "molecular shield". Moreover, the anti-aggregation activity of MpLEA1 was ten times greater than that of BSA or insect LEA proteins, which are known to prevent aggregation on drying. Here, we show that an ER-localized LEA protein, MpLEA1, possesses biochemical and structural features specific to group 3 LEA proteins.
authors.affiliation: National Institute of Agrobiological Sciences, 1-2 Ohwashi, Tsukuba 305-8634, Japan; Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan. Electronic address: hatanakarie@affrc.go.jp.
authors.forename: Rie
authors.initials: R
authors.lastname: Hatanaka
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-62, Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Furuki
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-62, Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Tempei
authors.initials: T
authors.lastname: Shimizu
authors.affiliation: Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takezawa
authors.affiliation: National Institute of Agrobiological Sciences, 1-2 Ohwashi, Tsukuba 305-8634, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kikawada
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-62, Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Sakurai
authors.affiliation: Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan.
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Sugawara
mesh_terms: D004721:Endoplasmic Reticulum / Q000378:metabolism*; D047008:Marchantia / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism*; D012639:Seeds / Q000166:cytology* / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; C066246:late embryogenesis abundant protein, plant
keywords: Desiccation tolerance; ER localization; Intrinsically disordered protein; LEA proteins; Marchantia polymorpha; Molecular shields