1WP1

Crystal structure of the drug-discharge outer membrane protein, OprM

1WP1 の概要

• エントリーDOI: 10.2210/pdb1wp1/pdb
• 分子名称: Outer membrane protein oprM (2 entities in total)
• 機能のキーワード: beta barrel, membrane protein
• 由来する生物種: Pseudomonas aeruginosa
• 細胞内の位置: Cell outer membrane; Lipid-anchor: Q51487
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 103475.21

構造登録者

Akama, H.,Kanemaki, M.,Yoshimura, M.,Tsukihara, T.,Kashiwagi, T.,Narita, S.,Nakagawa, A.,Nakae, T. (登録日: 2004-08-28, 公開日: 2004-11-02, 最終更新日: 2024-03-13)

主引用文献

Akama, H.,Kanemaki, M.,Yoshimura, M.,Tsukihara, T.,Kashiwagi, T.,Yoneyama, H.,Narita, S.,Nakagawa, A.,Nakae, T.
Crystal structure of the drug discharge outer membrane protein, OprM, of Pseudomonas aeruginosa: dual modes of membrane anchoring and occluded cavity end
J.Biol.Chem., 279:52816-52819, 2004

PubMed Abstract: The OprM lipoprotein of Pseudomonas aeruginosa is a member of the MexAB-OprM xenobiotic-antibiotic transporter subunits that is assumed to serve as the drug discharge duct across the outer membrane. The channel structure must differ from that of the porin-type open pore because the protein facilitates the exit of antibiotics but not the entry. For better understanding of the structure-function linkage of this important pump subunit, we studied the x-ray crystallographic structure of OprM at the 2.56-angstroms resolution. The overall structure exhibited trimeric assembly of the OprM monomer that consisted mainly of two domains: the membrane-anchoring beta-barrel and the cavity-forming alpha-barrel. OprM anchors the outer membrane by two modes of membrane insertions. One is via the covalently attached NH(2)-terminal fatty acids and the other is the beta-barrel structure consensus on the outer membrane-spanning proteins. The beta-barrel had a pore opening with a diameter of about 6-8 angstroms, which is not large enough to accommodate the exit of any antibiotics. The periplasmic alpha-barrel was about 100 angstroms long formed mainly by a bundle of alpha-helices that formed a solvent-filled cavity of about 25,000 angstroms(3). The proximal end of the cavity was tightly sealed, thereby not permitting the entry of any molecule. The result of this structure was that the resting state of OprM had a small outer membrane pore and a tightly closed periplasmic end, which sounds plausible because the protein should not allow free access of antibiotics. However, these observations raised another unsolved problem about the mechanism of opening of the OprM cavity ends. The crystal structure offers possible mechanisms of pore opening and pump assembly.

PubMed: 15507433
DOI: 10.1074/jbc.C400445200

実験手法

X-RAY DIFFRACTION (2.56 Å)