鱼腥蓝细菌PCC7120铁吸收机制

铁离子是鱼腥蓝细菌PCC7120进行呼吸作用、光合作用和固氮作用中相关酶的重要辅基之一,缺铁将严重影响蓝细菌的生存.富氧的生态环境中铁通常以不溶的Fe3+形式存在,不易被细胞吸收利用.低铁条件下,鱼腥蓝细菌PCC7120分泌能螯合铁离子的嗜铁素,通过外膜上相应的转运体将嗜铁素-铁复合物转运到细胞内.综述了近年来在嗜铁素的种类及其生物合成途径、铁吸收系统的组成和功能等方面的最新进展,分析了铁吸收系统的调控机制,为进一步开展鱼腥蓝细菌铁吸收机制的研究提供依据.

Iron Uptake by Anabaena sp. Strain PCC7120

As a cofactor in photosynthesis,respiration and nitrogen fixation,Iron is essential for cyanobacteria,and iron deficiency would affect the productivity.Iron is present in oxic ecosystems as insoluble iron(III) oxide minerals and thus is not readily available for living organisms to acquire and use.Under iron-limiting conditions,siderophores are exported from the Anabaena cell,where they chelate ferric ions in the environment.Specific ferric-siderophore complexes are recognized by cognate outer-membrane transporters,which initiate the process of iron transport into the cell where the iron becomes available for metabolic functions.Recent progress of siderophores including the types and their biosynthetic pathway was summarized.The components of the putative iron transport system was analyzed.The regulation mechanism of iron uptake was also discussed.This review would provide new evidence for advanced research on iron uptake by Anabaena.