SanG, a transcriptional activator, controls nikkomycin biosynthesis through binding to the sanN-sanO intergenic region in Streptomyces ansochromogenes.----中国科学院微生物研究所

科研成果

论文题目:	SanG, a transcriptional activator, controls nikkomycin biosynthesis through binding to the sanN-sanO intergenic region in Streptomyces ansochromogenes.
作者:	Xihong He, Rui Li, Yuanyuan Pan, Gang Liu* and Huarong Tan*
联系作者:	谭华荣
刊物名称:	Microbioogy-SGM
期:
卷:	156
页:	828
年份:	2010
影响因子:	3.025
论文下载:
摘要:	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 SARP domain, a central ATPase domain, and a C-terminal half homologous to guanylate cyclases belonging to LuxR family. SanG was expressed in Escherichia coli as a C-terminal His6-tagged protein. The purified SanG-His6 was shown to be a dimmer in solution by dynamic light scattering (DLS). An electrophoretic mobility-shift assay (EMSA) 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 polymerase chain reaction (RT-PCR) showed that mutation of ATPase/GTPase domain of SanG significantly decreased the transcriptional level of sanN-I and sanO-V. These results indicated that ATPase/GTPase activity of SanG modulated the transcriptional activation of SanG target genes during nikkomycin biosynthesis.