A Two-component Regulatory System Involved in Clavulanic Acid Production

Abstract

A pair of genes encoding the bacterial twocomponent 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/D orf23. Although growth and morphological analyses showed no differences between S. clavuligerus/D orf23 and wild-type, the production of clavulanic acid in S. clavuligerus/D orf23 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/D orf23 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.

Proteome-wide alterations in an industrial clavulanic acid producing strain of Streptomyces clavuligerus

“…From the 72 distinct putative TCS located in S. clavuligerus genome, only SCLAV_2102 was identified as 4.5 fold downrepresented in the DEPA strain, it might negatively regulate the formation of CA or CA precursors; however, the TCS orf22/23 described as positive regulator of CA formation [49] was not affected in the industrial strain. TCSs, as AbrA1/A2 or AbrC1/C2/C3 have been described to control antibiotic biosynthesis in S. coelicolor [50] and TCS inactivation has been shown to stimulate the biosynthesis of gougerotin in S. graminearus [51] , avermectin in S. avermitilis [52] and erythromycin in Saccharopolyspora erythraea [53] , which supports a role for SCLAV_2102 in CA regulation.…”

Improvement of clavulanic acid production in Streptomyces clavuligerus by genetic manipulation of structural biosynthesis genes

“…Our previous reports demonstrated that multicopy expression of regulatory genes enhanced CA production (Jnawali et al 2008;2010a). Based on these findings, we overexpressed and integrated four structural CA biosynthesis genes ceas2, bls2, cas2 and pah2 in wild-type S. clavuligerus.…”

“…CA production can be increased by the mutation of gap1 gene; overexpression and integration of regulator genes ccaR and claR in gap1-deleted mutant resulted in a 5-to 6-fold increase in CA production (Jnawali et al 2010a). CA production can be also increased by the over-expression of two-component regulatory genes (orf22 and orf23) (Jnawali et al 2008) and by the over-expression of sigma factor gene (orf21) (Jnawali et al 2010b). In this paper, we overexpressed and integrated four early stage biosynthetic structural genes (ceas2, bls2, cas2 and pah2) of CA from S. clavuligerus to assess their effect on CA production.…”

Streptomyces clavuligerus: The Producer Organism of Clavulanic Acid

“…Clavulanic acid can be increased also by genetic engineering through mutation of the gap1 gene. Through over expression and integration of regular genes ccaR and claR in gap1 deleted mutants resulted in a 5 to 6 fold increase in clavulanic acid production [14].…”