革兰氏阴性菌血红素转运系统结构及功能特点

铁是大多数生物包括细菌生存的必需营养元素．对于感染宿主的致病细菌,血红素(heme/haem)可作为一种主要的铁来源．血红素转运系统在革兰氏阴性菌和革兰氏阳性菌中均有发现和鉴定，其转运机制在革兰氏阴性菌中有较为深入研究．革兰氏阴性菌血红素转运系统主要由分泌于细胞外的血红素载体(hemophore)、血红素受体、TonB ExbB ExbD复合物、ABC转运体、血红素降解蛋白和调控蛋白等结构单元组成．对参与该系统的各个蛋白结构特点以及它们之间的相互作用机制的讨论，有助于对病原菌致病机制的深入研究和抗菌新药的研发．

Structural and Functional Properties of the Heme Acquisition System in Gram-negative Bacteria

Iron is an essential element for almost of organisms, including bacteria. For pathogenic bacteria, heme can be a main iron source. The heme acquisition systems have been extensively found and identified in both Gram-negative and Gram-positive bacteria. The mechanisms of heme uptake in Gram negative bacteria have been well-characterized. In Gram-negative bacteria, the heme acquisition system includes hemophore, heme receptor, TonB ExbB ExbD complex, ABC transporter, heme degrading protein and regulator proteins. The understanding to the structures and interactions of these proteins involved in heme uptake will help us to reveal the pathogenic mechanisms and develop new drugs to fight bacterial infections.