[Diversity of Cuproproteins and Copper Homeostasis Systems in Melioribacter roseus, a Facultatively Anaerobic Thermophilic Member of a New Phylum Ignavibacteriae]

Abstract

The genome of Melioribacter roseus, one of two members of the recently described phylum Ignavibacteriae, was searched for the genes encoding proteins associated with copper transport or containing copper as cofactors, and the effect of Cu2+ concentration in the medium on M. roseus growth was investigated. Genomic analysis revealed a variety of copper-containing oxidoreductases in this facultative anaerobe. Three ATPases responsible for copper transport were identified. One of them (MROS_1511) was.probably involved in assembly of the copper-containing cytochrome c oxidase, while two others (MROS_0327 and MROS_0791) probably carried out a detoxification function. The presence of several copper-containing oxidoreductases and copper homeostasis systems in M. roseus is in agreement with the previously hypothesized origin of the phylum Ignavibacteriae from an aerobic ancestor common with those of Bacteroidetes and Chlorobi.