Interaction of coatomer with aminoglycoside antibiotics: Evidence that coatomer has at least two dilysine binding sites
Interaction of coatomer with aminoglycoside antibiotics: Evidence that coatomer has at least two dilysine binding sites
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DOI：
10.1091/mbc.8.10.1901
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发表时间：
1997-10-01
影响因子：
3.3
通讯作者：
Draper, RK
中科院分区：
文献类型：
--
作者：
Hudson, RT;Draper, RK
包衣体是参与内质网和高尔基体膜间运输的COPI被膜（被膜蛋白I）的可溶性前体。我们在此报告了新霉素从细胞提取物和纯化的涂层制剂中析出涂层。随着新霉素浓度的增加，沉淀先增加后减少，类似于二价抗体对多价抗原的沉淀。这表明新霉素交联包衣体形成大的聚集体，并暗示包衣体具有两个或更多的新霉素结合位点。各种其他氨基糖苷类抗生素沉淀涂层，或者即使不沉淀，也会干扰新霉素的沉淀能力。已知Coatomer与一个基序（KKXX）相互作用，该基序在内质网中一些膜蛋白的细胞质结构域的羧基端含有邻近的赖氨酸残基。所有与涂层相互作用的抗生素都含有至少两个紧密的氨基，表明抗生素可能与涂层的二赖氨酸结合位点相互作用。与这一观点一致的是，二赖氨酸本身阻断了抗生素与涂层的相互作用。此外，二赖氨酸和抗生素均阻断了涂层对高尔基膜的包衣。这些数据表明，某些氨基糖苷类抗生素与涂层上的二赖氨酸结合位点相互作用，并且涂层至少含有两个这些二赖氨酸结合位点。
Coatomer is the soluble precursor of the COPI coat (coat protein I) involved in traffic among membranes of the endoplasmic reticulum and the Golgi apparatus. We report herein that neomycin precipitates coatomer from cell extracts and from purified coatomer preparations. Precipitation first increased and then decreased as the neomycin concentration increased, analogous to the precipitation of a polyvalent antigen by divalent antibodies. This suggested that neomycin cross-linked coatomer into large aggregates and implies that coatomer has two or more binding sites for neomycin. A variety of other aminoglycoside antibiotics precipitated coatomer, or if they did not precipitate, they interfered with the ability of neomycin to precipitate. Coatomer is known to interact with a motif (KKXX) containing adjacent lysine residues at the carboxyl terminus of the cytoplasmic domains of some membrane proteins resident in the endoplasmic reticulum. All of the antibiotics that interacted with coatomer contain at least two close amino groups, suggesting that the antibiotics might be interacting with the di-lysine binding site of coatomer. Consistent with this idea, di-lysine itself blocked the interaction of antibiotics with coatomer. Moreover, di-lysine and antibiotics each blocked the coating of Golgi membranes by coatomer. These data suggest that certain aminoglycoside antibiotics interact with di-lysine binding sites on coatomer and that coatomer contains at least two of these di-lysine binding sites.