CopM is a novel copper-binding protein involved in copper resistance in Synechocystis sp. PCC 6803.

摘要: Copper resistance system in the cyanobacterium Synechocystis sp. PCC 6803 comprises two operons, copMRS and copBAC, which are expressed response to copper media. copBAC codes for a heavy-metal efflux–resistance nodulation division (HME-RND) system, while protein of unknown function, CopM, two-component CopRS, controls expression these operons. Here, we report that CopM is periplasmic able bind Cu(I) with high affinity (KD ~3 × 10−16). Mutants lacking copM showed sensitive phenotype similar mutants affected copB, but lower than suggesting CopBAC constitute independent mechanisms. Moreover, constitutive partially suppress sensitivity copR mutant strain, pointing out per se confer resistance. Furthermore, was reduce total cellular content levels determined wild-type (WT) strain. Finally, localized not only periplasm also extracellular space, can prevent accumulation probably by direct binding outside cell.