@article{mbs:/content/journal/micro/10.1099/mic.0.033605-0, author = "He, Xihong and Li, Rui and Pan, Yuanyuan and Liu, Gang and Tan, Huarong", title = "SanG, a transcriptional activator, controls nikkomycin biosynthesis through binding to the sanN–sanO intergenic region in Streptomyces ansochromogenes", journal= "Microbiology", year = "2010", volume = "156", number = "3", pages = "828-837", doi = "https://doi.org/10.1099/mic.0.033605-0", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.033605-0", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "SARP, Streptomyces antibiotic regulatory protein", keywords = "EMSA, electrophoretic mobility-shift assay", abstract = " Streptomyces ansochromogenes SanG is a pathway-specific regulator that mainly controls the transcription of two transcriptional units involved in nikkomycin biosynthesis. SanG consists of three major functional domains: an N-terminal Streptomyces antibiotic regulatory protein (SARP) domain, a central ATPase domain, and a C-terminal half homologous to guanylate cyclases belonging to the LuxR family. SanG was expressed in Escherichia coli as a C-terminally His6-tagged protein. The purified SanG-His6 was shown to be a dimer in solution by dynamic light scattering. An electrophoretic mobility-shift assay showed that the purified SanG protein could bind to the DNA fragment containing the bidirectional sanN–sanO promoter region. The SanG-binding sites within the bidirectional sanN–sanO promoter region were determined by footprinting analysis and identified a consensus-directed repeat sequence 5′-CGGCAAG-3′. SanG showed significant ATPase/GTPase activity in vitro, and addition of ATP/GTP enhanced the affinity of SanG for target DNA, but ATP/GTP hydrolysis was not essential for SanG binding to the target DNA. However, real-time reverse transcription PCR showed that mutation of the ATPase/GTPase domain of SanG significantly decreased the transcriptional level of sanN–I and sanO–V. These results indicated that the ATPase/GTPase activity of SanG modulated the transcriptional activation of SanG target genes during nikkomycin biosynthesis.", }