A two-component regulatory system involved in clavulanic acid production.

A pair of genes encoding the bacterial two-component regulatory system, orf22 and orf23, was found next to the clavulanic acid gene cluster of Streptomyces clavuligerus NRRL3585. Orf23 was deleted for the construction of S. clavuligerus/Deltaorf23. Although growth and morphological analyses showed no differences between S. clavuligerus/Deltaorf23 and wild-type, the production of clavulanic acid in S. clavuligerus/Deltaorf23 was found to be decreased. In addition, the co-overexpression of orf22/orf23 in wild-type resulted in an enhanced 1.49-fold production of clavulanic acid, and the complementation of orf22/orf23 in S. clavuligerus/Deltaorf23 restored clavulanic acid production about 80% as normal levels. These results demonstrate that the orf22/orf23 two-component regulatory system participates as a positive regulator of the biosynthesis of clavulanic acid and increased levels of orf22/orf23 can contribute to enhanced production of clavulanic acid in S. clavuligerus.