Regulation Of dehalogenase E (DehE) and expression of dehalogenase regulator gene (DehR) from Rhizobium sp RC1 in E. coli

Abstract

The DNA sequence upstream of dehE gene encoding dehalogenase E (DehE) of Rhizobium sp. RC1 was determined and contained an open reading frame, designated dehR, which encoded a protein with a significant similarity to dehalogenase regulatory protein (DehR). Plasmid DNA designated pFH648 that carry both dehE and dehR genes were cloned from Rhizobium sp. RC1 genomic DNA. The Rhizobium sp. RC1 genetic organization was determined, suggesting dehE was controlled by the product of dehR. Current study proved that by growth experiment, E. coli XL10 Gold::pFH648 (dehE+, dehR+) has the ability to grow in minimal media supplied with 20 mM D,L-2-chloropropionic acid (D,L-2CP) as sole source of carbon. E. coli XL10::pSC520 (dehE+) lacking dehR gene and E. coli XL10 Gold::pFH45 (dehR+) lacking dehE gene did not grow in minimal media supplied with 20 mM D,L-2CP as sole source of carbon and energy, suggesting both dehE and dehR genes were needed to allow growth in D,L-2CP minimal media. Since the genetic organisation for both dehE and dehR were neighbouring genes similar to that of Pseudomonas putida PP3 dehRI and dehI, promoters were predicted to be present for both dehE and dehR genes.