STRUCTURE AND FUNCTION OF X-PRO DIPEPTIDE REPEATS IN THE TONB PROTEINS OF SALMONELLA-TYPHIMURIUM AND ESCHERICHIA-COLI
STRUCTURE AND FUNCTION OF X-PRO DIPEPTIDE REPEATS IN THE TONB PROTEINS OF SALMONELLA-TYPHIMURIUM AND ESCHERICHIA-COLI
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DOI：
10.1016/s0022-2836(99)80008-4
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发表时间：
1990-12-20
影响因子：
5.6
通讯作者：
WORMALD, MR
中科院分区：
文献类型：
--
作者：
BREWER, S;TOLLEY, M;WORMALD, MR
TonB蛋白在细菌的几个外膜运输过程中是必需的。利用1H和13C核磁共振波谱对TonB的短肽段进行了研究。该肽段的序列包含多个Glu-Pro和Lys-Pro二肽重复序列，它们保持刚性、细长的结构，并位于采用。beta的短连接段的侧面。链配置。这种TonB肽被证明与FhuA蛋白（铁素铁的外膜受体）特异性相互作用，提供了TonB蛋白与外膜受体相互作用的第一个直接证据。与FhuA蛋白的相互作用涉及包含带正电荷的Lys-Pro重复序列的扩展结构元件，并表明TonB蛋白的这一部分具有功能作用。由于TonB固定在细胞质膜上，这种蛋白必须独特地跨越细胞质周。这些数据，连同论文中描述的研究，提出了一个模型，通过该模型，TonB可以在从细胞质膜到外膜的较长距离上传递构象信息。
The TonB protein is required for several outer membrane transport processes in bacteria. A short 33-residue peptide segment of TonB has been studied by 1H and 13C nuclear magnetic resonance spectroscopy. The sequence of this peptide segment contains multiple Glu-Pro and Lys-Pro dipeptide repeats that maintain rigid, elongated structures and flank a short connecting segment that adopts a .beta.-strand configuration. This TonB peptide is shown to interact specifically with a FhuA protein, the outer membrane receptor for ferrichrome-iron, providing the first direct evidence that the TonB proteins interacts with outer membrane receptors. Interaction with the FhuA protein involves the extended structural element containing positively charged Lys-Pro repeats, and suggests a functional role for this segment of the TonB protein. As TonB is anchored in the cytoplasmic membrane the protein must, uniquely, span the periplasm. These data, together with studies described in the accompanying paper, suggest a model by which TonB serves to transduce conformational information over extended distances, from the cytoplasmic membrane to the outer membrane.