Iron is an important metal in several cellular processes and it is found in high amounts in the heme group of hemoproteins, like hemoglobin. To exploit this abundant source of iron in the host many pathogens have heme uptake and degradation mechanisms. In this work we aim to identify these mechanisms in the bacterium Chromobacterium violaceum, a Gram-negative beta-proteobacterium found in soil and water of tropical regions, that causes severe opportunistic infections in humans. In silico analysis of C. violaceum ATCC 12472 genome revealed the chuPRSTUV operon as a candidate to encode a heme uptake and degradation system. To characterize this system, mutant strains will be obtained by allelic exchange with deletion of the complete operon and individual genes. The mutants will be characterized by in vitro heme utilization assays and in vivo mouse virulence assays. Furthermore, in vitro biochemical assays will be performed with the purified proteins ChuP and ChuS to determine their roles in regulation of the chuPRSTUV operon and heme degradation, respectively. Together, the data obtained from this work will help to elucidate the strategies that C. violaceum uses to uptake and degrade heme from the environment and the host, and the importance of heme in the pathogenesis of this bacterium.
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