革兰氏阴性菌TonB依赖性受体的功能与结构研究进展

A Review on Structure and Functions of TonB-dependent Receptors in Gram-negative Bacteria

为维持生长所需,革兰氏阴性菌需要从外界摄取多种营养物质。分子量小于600 Da的分子可以通过自由扩散的方式通过革兰氏阴性菌的外膜,而大分子物质则需要特殊的转运系统才能将其转运至革兰氏阴性菌的胞内。革兰氏阴性菌对大分子营养物质的识别和转运主要由TonB依赖性受体负责完成。所有革兰氏阴性菌中均有TonB依赖性受体的存在,然而不同种类的革兰氏阴性菌拥有TonB依赖性受体的数量不同且功能各异。最近研究表明,TonB依赖性受体不仅参与了铁、血红素、锰、锌、镍、维生素、碳水化合物等多种营养物质的摄取,而且参与了蛋白酶的分泌。为对TonB依赖性受体提供更为深入和系统的理解,详细介绍了目前已知的TonB依赖性受体的功能及结构,以期为更进一步探知TonB依赖性受体未知功能提供可参考依据。

Bacteria need to absorb a variety of nutrients from the outer environments for their survival and replication.The small molecules less than 600 Da can freely pass the outer membrane of the gram-negative bacteria.However,for the transportation of the large size of nutrients,the TonB-dependent receptors of gram-negative bacteria are required.TonB-dependent receptors have been found to be present in all the sequenced gram-negative bacteria,but the number of TonB dependent receptors and their functions are various in different bacteria.It has been shown that TonB-dependent receptors were not only involved in the transportation of many different nutrients,such as iron,heme,manganese,zinc,vitamin,and carbohydrate,but also the secretion of protease.This review provided detailed information about the functions and structure of TonB-dependent receptors from different gram-negative bacteria.It will be helpful for the further understanding of the new functions of TonB-dependent receptors.