Rhamnose Links Moonlighting Proteins to Membrane Phospholipid in Mycoplasmas.
Rhamnose Links Moonlighting Proteins to Membrane Phospholipid in Mycoplasmas.
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DOI：
10.1371/journal.pone.0162505
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Dybvig K
中科院分区：
文献类型：
--
作者：
Daubenspeck JM;Liu R;Dybvig K
许多蛋白质的主要功能是作为细胞质蛋白质，已知它们能够在几乎所有生物体的表面月光化。一个例子是糖酵解酶烯醇化酶，它可以在从细菌到人类的许多类型的细胞表面上找到。表面烯醇化酶不是酶，因为它是单体的，并且糖酵解活性需要寡聚化。它可以结合各种分子并激活纤溶酶原。烯醇化酶缺乏信号肽，其附着于表面的机制尚不清楚。我们发现，用磷脂酶D处理鼠病原体肺支原体的全细胞释放烯醇化酶和其他常见的兼职蛋白质。糖染色表明释放的蛋白质被糖基化。通过免疫沉淀分离胞质和膜结合的烯醇化酶。胞质烯醇化酶未检测到翻译后修饰，但膜烯醇化酶与脂质、磷酸盐和鼠李糖相关。磷脂酶处理释放的脂质和磷酸从烯醇化酶，但不是鼠李糖。鼠李糖基化位点被鉴定为蛋白质C-末端附近的谷氨酰胺残基。鼠李糖已被发现在所有种属的支原体检查，但其功能是未知的。支原体是没有肽聚糖的小细菌，这些生物体中的鼠李糖也不与多糖相关。我们认为，鼠李糖锚定蛋白质的膜连接磷脂，这可能是一个通用的机制，在支原体和其他细菌的兼职蛋白质的膜协会的核心作用。
Many proteins that have a primary function as a cytoplasmic protein are known to have the ability to moonlight on the surface of nearly all organisms. An example is the glycolytic enzyme enolase, which can be found on the surface of many types of cells from bacteria to human. Surface enolase is not enzymatic because it is monomeric and oligomerization is required for glycolytic activity. It can bind various molecules and activate plasminogen. Enolase lacks a signal peptide and the mechanism by which it attaches to the surface is unknown. We found that treatment of whole cells of the murine pathogen Mycoplasma pulmonis with phospholipase D released enolase and other common moonlighting proteins. Glycostaining suggested that the released proteins were glycosylated. Cytoplasmic and membrane-bound enolase was isolated by immunoprecipitation. No post-translational modification was detected on cytoplasmic enolase, but membrane enolase was associated with lipid, phosphate and rhamnose. Treatment with phospholipase released the lipid and phosphate from enolase but not the rhamnose. The site of rhamnosylation was identified as a glutamine residue near the C-terminus of the protein. Rhamnose has been found in all species of mycoplasma examined but its function was previously unknown. Mycoplasmas are small bacteria with have no peptidoglycan, and rhamnose in these organisms is also not associated with polysaccharide. We suggest that rhamnose has a central role in anchoring proteins to the membrane by linkage to phospholipid, which may be a general mechanism for the membrane association of moonlighting proteins in mycoplasmas and perhaps other bacteria.
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影响因子：
3.6
作者：
Jordan DS;Daubenspeck JM;Laube AH;Renfrow MB;Dybvig K
通讯作者：
Dybvig K
影响因子：
5.3
作者：
Kornspan JD;Rottem S
通讯作者：
Rottem S
影响因子：
56.9
作者：
FRASER, CM;GOCAYNE, JD;VENTER, JC
通讯作者：
VENTER, JC
影响因子：
--
作者：
Hoelzle, Ludwig E.;Hoelzle, Katharina;Wittenbrink, Max M.
通讯作者：
Wittenbrink, Max M.
影响因子：
6.7
作者：
López-Alemany, R;Suelves, M;Muñoz-Cánoves, P
通讯作者：
Muñoz-Cánoves, P