Structures of the OmpF porin crystallized in the presence of foscholine-12

Authors

  • Georgia Kefala,

    1. Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd., La Jolla, California 92037
    2. The Center for Structures of Membrane Proteins (CSMP), UCSF Mission Bay Campus, S414 Genentech Hall, 600 16th Street, San Francisco, California, 94107
    3. Joint Center for Biosciences, Incheon 406-840, Korea
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  • Chihoon Ahn,

    1. Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd., La Jolla, California 92037
    2. The Center for Structures of Membrane Proteins (CSMP), UCSF Mission Bay Campus, S414 Genentech Hall, 600 16th Street, San Francisco, California, 94107
    3. Joint Center for Biosciences, Incheon 406-840, Korea
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  • Martin Krupa,

    1. Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd., La Jolla, California 92037
    2. The Center for Structures of Membrane Proteins (CSMP), UCSF Mission Bay Campus, S414 Genentech Hall, 600 16th Street, San Francisco, California, 94107
    3. Joint Center for Biosciences, Incheon 406-840, Korea
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  • Luis Esquivies,

    1. Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd., La Jolla, California 92037
    2. The Center for Structures of Membrane Proteins (CSMP), UCSF Mission Bay Campus, S414 Genentech Hall, 600 16th Street, San Francisco, California, 94107
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  • Innokentiy Maslennikov,

    1. Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd., La Jolla, California 92037
    2. The Center for Structures of Membrane Proteins (CSMP), UCSF Mission Bay Campus, S414 Genentech Hall, 600 16th Street, San Francisco, California, 94107
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  • Witek Kwiatkowski,

    1. Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd., La Jolla, California 92037
    2. The Center for Structures of Membrane Proteins (CSMP), UCSF Mission Bay Campus, S414 Genentech Hall, 600 16th Street, San Francisco, California, 94107
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  • Senyon Choe

    Corresponding author
    1. Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd., La Jolla, California 92037
    2. The Center for Structures of Membrane Proteins (CSMP), UCSF Mission Bay Campus, S414 Genentech Hall, 600 16th Street, San Francisco, California, 94107
    3. Joint Center for Biosciences, Incheon 406-840, Korea
    • Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Rd., La Jolla, CA 92037
    Search for more papers by this author

Abstract

The endogenous Escherichia coli porin OmpF was crystallized as an accidental by-product of our efforts to express, purify, and crystallize the E. coli integral membrane protein KdpD in the presence of foscholine-12 (FC12). FC12 is widely used in membrane protein studies, but no crystal structure of a protein that was both purified and crystallized with this detergent has been reported in the Protein Data Bank. Crystallization screening for KdpD yielded two different crystals of contaminating protein OmpF. Here, we report two OmpF structures, the first membrane protein crystal structures for which extraction, purification, and crystallization were done exclusively with FC12. The first structure was refined in space group P21 with cell parameters a = 136.7 Å, b = 210.5 Å, c = 137 Å, and β = 100.5°, and the resolution of 3.8 Å. The second structure was solved at the resolution of 4.4 Å and was refined in the P321 space group, with unit cell parameters a = 215.5 Å, b = 215.5 Å, c = 137.5 Å, and γ = 120°. Both crystal forms show novel crystal packing, in which the building block is a tetrahedral arrangement of four trimers. Additionally, we discuss the use of FC12 for membrane protein crystallization and structure determination, as well as the problem of the OmpF contamination for membrane proteins overexpressed in E. coli.

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