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首页> 外文期刊>Journal of bacteriology >Functional mosaicism of membrane proteins in vesicles of Escherichia coli.
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Functional mosaicism of membrane proteins in vesicles of Escherichia coli.

机译：大肠杆菌囊泡中膜蛋白的功能镶嵌。

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Membrane vesicles of Escherichia coli prepared by osmotic lysis of lysozyme ethylenediaminetetracetate (EDTA) spheroplasts have approximately 60% of the total membrane-bound reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase (ED 1.6.99.3) and Mg2+-adenosine triphosphatase (ATPase) (EC 3.6.1.3) activities exposed on the outer surface of the inner membrane. Absorption of these vesicles with antiserum prepared against the purified soluble Mg2+-ATPase resulted in agglutination of approximately 95% of the inner membrane vesicles, as determined by dehydrogenase activity, and about 50% of the total membrane protein. The unagglutinated vesicles lacked all dehydrogenase activity and may consist of outer membrane. Lysozyme-EDTA vesicles actively transported calcium ion, using either NADH or adenosine 5'-triphosphate (ATP) as energy source. However, neither D-lactate nor reduced phenazine methosulfate energized calcium uptake, suggesting that the observed calcium uptake was not due to a small population of everted vesicles. Transport of calcium driven by either NADH or ATP was inhibited by simultaneous addition of D-lactate or reduced phenazine methosulfate. Proline transport driven by D-lactate oxidation was inhibited by either NADH oxidation or ATP hydrolysis. These results suggest that the portion of the total population of vesicles capable of active transport, i.e., the inner membrane vesicles, are functionally a homogeneous population but cannot be categorized as either right-side-out or everted, since activities normally associated with only one side of the inner membrane can be found on both sides of the membrane of these vesicles. Moreover, the data indicate that oxidation of NADH or hydrolysis of ATP by externally localized NADH dehydrogenase or Mg2+-ATPase establishes a protonmotive force of the opposite polarity from that established through D-lactate oxidation.
机译：通过溶菌酶乙二胺四乙酸（EDTA）原生质体渗透裂解制备的大肠杆菌膜囊泡，约占膜结合的还原烟酰胺腺嘌呤二核苷酸（NADH）脱氢酶（ED 1.6.99.3）和Mg2 +-腺苷三磷酸酶（ATP）总量的60％ 3.6.1.3）活动暴露在内膜的外表面。用针对纯化的可溶性Mg2 + -ATPase制备的抗血清吸收这些囊泡会导致大约95％的内膜囊泡凝集（通过脱氢酶活性测定）和大约50％的总膜蛋白凝集。未凝集的囊泡缺乏所有脱氢酶活性，可能由外膜组成。溶菌酶-EDTA囊泡利用NADH或5'-三磷酸腺苷（ATP）作为能源主动转运钙离子。然而，D-乳酸盐或吩嗪甲基硫酸盐均未激发钙的摄取，这表明观察到的钙摄取不是由于小泡状囊泡群体引起的。同时添加D-乳酸或还原的吩嗪甲硫酸盐可抑制由NADH或ATP驱动的钙转运。由D-乳酸氧化驱动的脯氨酸转运受到NADH氧化或ATP水解的抑制。这些结果表明，能够主动转运的总囊泡的一部分，即内膜囊泡，在功能上是均一的，但不能归类为右向外或外翻，因为活动通常仅与一个相关。内膜的侧面可以在这些囊泡的膜的两侧找到。而且，数据表明，通过外部定位的NADH脱氢酶或Mg2 + -ATP酶对NADH的氧化或ATP的水解建立了与通过D-乳酸氧化建立的极性相反的质子动力。

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