@article{mbs:/content/journal/micro/10.1099/mic.0.081141-0, author = "He, Weiqing and Li, Guoqing and Yang, Chun-Kai and Lu, Chung-Dar", title = "Functional characterization of the dguRABC locus for d-Glu and d-Gln utilization in Pseudomonas aeruginosa PAO1", journal= "Microbiology", year = "2014", volume = "160", number = "10", pages = "2331-2340", doi = "https://doi.org/10.1099/mic.0.081141-0", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.081141-0", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = " d-Glu, an essential component of peptidoglycans, can be utilized as a carbon and nitrogen source by Pseudomonas aeruginosa. DNA microarrays were employed to identify genes involved in d-Glu catabolism. Through gene knockout and growth phenotype analysis, the divergent dguR–dguABC (d-Glu utilization) gene cluster was shown to participate in d-Glu and d-Gln catabolism and regulation. Growth of the dguR and dguA mutants was abolished completely on d-Glu or retarded on d-Gln as the sole source of carbon and/or nitrogen. The dguA gene encoded a FAD-dependent d-amino acid dehydrogenase with d-Glu as its preferred substrate, and its promoter was specifically induced by exogenous d-Glu and d-Gln. The function of DguR as a transcriptional activator of the dguABC operon was demonstrated by promoter activity measurements in vivo and by mobility shift assays with purified His-tagged DguR in vitro. Although the DNA-binding activity of DguR did not require d-Glu, the presence of d-Glu, but not d-Gln, in the binding reaction was found to stabilize a preferred nucleoprotein complex. The presence of a putative DguR operator was revealed by in silica analysis of the dguR–dguA intergenic regions among Pseudomonas spp. and binding of DguR to a highly conserved 19 bp sequence motif was further demonstrated. The dguB gene encodes a putative enamine/imine deaminase of the RidA family, but its role in d-Glu catabolism remains to be determined. Whilst a lesion in dguC encoding a periplasmic solute binding protein only affected growth on d-Glu slightly, expression of the previously characterized AatJMQP transporter for acidic l-amino acid uptake was found inducible by d-Glu and essential for d-Glu utilization. In summary, the findings of this study supported DguA as a new member of the FAD-dependent d-amino acid dehydrogenase family, and DguR as a d-Glu sensor and transcriptional activator of the dguA promoter.", }