Conjugal transfer of this RpoN expression vector into P. putida CA-3 D7 (carrying a Tn5::rpoN gene disruption), was performed by tri-parental mating with the p38 protein kinase Top 10F’ E. coli host and the HB101(pRK600) helper, as previously described. P. putida CA-3 D7 transconjugants were isolated from the mating mix by spread plating 50 μl aliquots onto minimal salts media containing10 mM citrate and 20 μg/ml gentamycin. The pBBR1MCS-5 vector, (lacking any insert), was also transferred into P. putida CA-3 wild type and D7 mutant strains to provide controls for subsequent growth studies. All growth curves were conducted in triplicate.

Cloning and over expression of the phenylacetate permease, PaaL Degenerate paaL primers, harbouring similar mis-primed restriction enzyme sites as before (paaLf-Hind & paaLr-Xba, Table 2), were designed based on sequence data from P. fluorescens ST and Pseudomonas sp. Y2, [20, 22]. Cloning, screening and vector/insert confirmation in the Top 10F’ E. coli host was conducted as described previously.

Tri-parental mating to achieve conjugal transfer of the vector into rpoN disrupted P. putida CA-3 cells was also performed as before. Transconjugants were subsequently screened for any restoration of the ability to grow in minimal salts media with phenylacetic acid as the sole carbon source. To determine GS-1101 mw whether strict regulation of PaaL expression represented a rate limiting feature of extracellular phenylacetic RG7112 supplier acid utilisation in wild type P. putida CA-3, the PaaL expression vector was also conjugally transferred into the parent strain. RT-PCR analysis was employed to confirm constitutive expression of PaaL from the vector under non inducing growth on minimal salts citrate. Over expression strains were subsequently grown in minimal salts media with phenylacetic acid to facilitate growth profiling and PACoA ligase activity determination. All growth

curves were conducted in triplicate. It should be noted that a degenerate pcr strategy was employed to screen anti-EGFR antibody the P. putida CA-3 genome for a paaM permease gene homologue, but none was detected. Isolation and analysis of the paaL promoter Primers were designed to amplify the promoter region of the paaL gene based on the sequence data of the PACoA catabolon of Pseudomonas sp. strain Y2. The primer set (paaLproF and paaLproR, Table 2), amplified a 964 base pair region spanning the 3′ end of the paaG gene, the intergenic region and the 5′ end of paaL. The complete paaL gene and promoter region have been submitted to GenBank, (Accession number HM638062). A number of putative σ54 dependent promoters of transport proteins from the P.