Abstract:[Background] MvaT protein belonging to the H-NS transcription factor family is involved in many important metabolic processes of Pseudomonas aeruginosa, such as phenazine synthesis pathway. However, up to now its regulation mode is still unclear. [Objective] The goal of this work was to determine if MvaT could directly regulate the two phenazine-1-carboxylic acid synthesis gene clusters (phzA1G1 and phzA2G2) and three transforming genes (phzH, phzS and phzM) of phenazine compounds, by detecting the binding capability of MvaT to the promoter regions of these genes. [Methods] Pseudomonas aeruginosa SJTD-1 was used as target and the mvaT-knockout strain SJTD-1(ΔmvaT) was constructed by homologous recombination. The yield of phenazine compounds of the two strains in different media was detected. Further the recombinant MvaT protein was obtained by the heterologous expression and affinity purification. The electrophoretic mobility shift assay (EMSA) was performed to determine if the recombinant MvaT protein could bind to the promoter regions of the five phenazine synthetic gene clusters/genes. [Results] The yield of phenazine compounds of strain SJTD-1(ΔmvaT) was significantly higher than that of the wild type SJTD-1 strain. The recombinant MvaT protein could be expressed and purified efficiently. In vitro EMSA results indicated that the recombinant MvaT protein could directly bind to the promoter regions of phenazine synthetic gene clusters/genes. The binding sites of MvaT to the promoter of phzA1G1 and phzA2G2 gene clusters were within the upstream 200 bp region, and that to the promoter of phzM, phzS and phzH genes were within its upstream 100 bp region. [Conclusion] MvaT protein can directly bind the upstream promoter regions of the five phenazine synthetic gene clusters/genes and regulate the synthesis of phenazine compounds.
