Petrobactin biosynthesis: AsbB catalyzes condensation of spermidine with N~8-citryl-spermidine and its N~1-(3,4-dihydroxybenzoyl) derivative

摘要

The AsbB enzyme, which is involved in the biosynthesis of the virulence-conferring siderophore petrobactin in Bacillus anthra-cis, is shown to catalyze efficient ATP-dependent condensation of spermidine, but not N~1-(3,4-dihydroxbenzoyl)-spermidine, with N~8-citryl-spermidine or N~1-(3,4-dihydroxbenzoyl)-N~8-citryl-spermidine, suggesting that N~1-(3,4-dihydroxbenzoyl)-spermidine is very unlikely to be a significant intermediate in petrobactin biosynthesis, contrary to previous suggestions.rnIron is an essential trace element for almost all living organisms. Despite being the fourth most abundant element on Earth's crust, its predominant presence as insoluble polymeric oxo-hydroxy complexes makes iron bioavailability very low in the environment. Therefore, in order to meet their iron requirements, many microorganisms have evolved the ability to produce and excrete small molecules with a high affinity for iron called siderophores. Once a siderophore has scavenged iron from its environment, the ferric-siderophore complex is actively taken up by microbial cells.