Inter-chain transacylation of D-alanine ester residues of lipoteichoic acid: a unique mechanism of membrane communication.
Inter-chain transacylation of D-alanine ester residues of lipoteichoic acid: a unique mechanism of membrane communication.
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脂磷壁酸 D-丙氨酸酯残基的链间转酰基作用：一种独特的膜通讯机制。
DOI：
10.1042/bst0130987
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发表时间：
1985
影响因子：
3.9
通讯作者：
Neuhaus,FC
中科院分区：
文献类型：
--
作者：
Neuhaus,FC
脂磷壁酸是两亲性物质的一个重要例子，它似乎在细菌生长中发挥着至关重要的作用。这种聚合物具有许多功能。这些包括自溶酶的调节，镁离子与酶功能的结合，以及壁上聚合物的组装。已提出的调节这些功能的关键成分之一是取代基D-丙氨酸。James Baddiley和他的同事发现，这种氨基酸是大多数磷壁酸的重要成分(Armstrong等人，1959)。因此，磷壁酸与D-丙氨酸的酯化反应可能是控制这种聚合物在壁面组装中功能的重要步骤。在干酪乳杆菌中，D-丙氨酸与脂磷壁酸的结合是通过两步反应序列完成的。这一序列的第一步是在1960年发现的，当时Baddiley&Neuhaus证明了各种革兰氏阳性生物具有激活D-丙氨酸的能力。这一序列的第二步直到Reusch&Neuhaus(1971)认识到D-丙氨酸在体外掺入磷壁酸需要内源性膜磷壁酸作为受体才被检测到。所有证明D-丙氨酸与分离的壁磷壁酸结合的尝试都被证明是难以捉摸的，并推论磷壁酸必须在特定的构象或环境中与膜紧密结合(Neuhaus等人，1974)。在这一假设的基础上，发现了一种D-丙氨酸掺入膜的体系，该体系需要上清液部分和三磷酸腺苷，并受到金属离子的刺激。Linzer&Neuhaus(1973)指出，上清液可以被D-丙氨酸激活酶和一种称为D-丙氨酸的蛋白质因子所取代：膜受体连接酶。选择干酪乳杆菌进行这些实验是因为，首先，它含有高浓度的
Lipoteichoic acid is an important example of an amphiphile that appears to play a vital role in bacterial growth. A number of functions have been ascribed to this polymer. These include the regulation of autolytic enzymes, the binding of Mgz+ for enzyme function, and the assembly of wall polymers. One of the key components which has been proposed to modulate these functions is the substituent D-alanine. James Baddiley and his co-workers discovered that this amino acid is an important component of most teichoic acids (Armstrong et al., 1959). Thus, esterification of teichoic acids by D-alanine may be an important step in controlling the function of this polymer in wall assembly. In Lactobacillus casei the incorporation of D-alanine into lipoteichoic acid is accomplished in a two-step reaction sequence. The first step of this sequence was discovered in 1960 when Baddiley & Neuhaus showed that a variety of Gram-positive organisms have the ability to activate D-alanine. The second step of this sequence was not detected until Reusch & Neuhaus (1971) recognized that the incorporation of D-alanine into teichoic acids in vitro required the endogenous membrane teichoic acid to act as acceptor. All attempts to demonstrate the incorporation of D-alanine into isolated wall teichoic acid proved to be elusive and it was reasoned that the teichoic acid has to be intimately associated with the membrane in a particular conformation or environment (Neuhaus et aZ., 1974). On the basis of this hypothesis a system for the incorporation of D-alanine into membranes was found that required both a supernatant fraction and ATP, and was stimulated by metal ions. Linzer & Neuhaus (1973) showed that the supernatant fraction could be replaced by the D-alanine-activating enzyme and a protein factor designated D-alanine: membrane acceptor ligase. L. casei was chosen for these experiments because, firstly, it has a high concentration of the