Chitinase Inhibitor Allosamidin Is a Signal Molecule for Chitinase Production in Its Producing Streptomyces

In Streptomyces sp. AJ9463, a producer of chitinase inhibitor allosamidin, allosamidin strongly enhances production of the chitinase mainly secreted to the culture broth in a chitin medium. To clarify the mechanism for regulation of the chitinase production by allosamidin, a disruption experiment of genes encoding proteins constructing a two-component regulatory system present at 5[variant prime]-upstream region of the chitinase gene was performed. In the disruptant obtained, allosamidin could not promote the chitinase production, but N,N[variant prime]-diacetylchitobiose, which also enhances production of the same chitinase more weakly than allosamidin, promoted the chitinase production similarly to the case observed in the wild-type strain. Furthermore, by the experiment in an inorganic salt solution, it was shown that allosamidin could not induce the chitinase production without addition of N,N[variant prime]-diacetylchitobiose. These results show that allosamidin can activate transcription of the chitinase gene through the two-component regulatory system in the presence of N,N[variant prime]-diacetylchitobiose.