, 2009). The analysis of RepB from pPRH revealed one conserved domain homologous to region 4 of sigma-70-like sigma factors, which is involved this website in binding of the −35 promoter element (Campbell et al., 2002). The RepB protein of pAL5000 was shown to bind to DNA near the ori site (Stolt & Stoker, 1996b). It could be proposed that the RepB encoded by pPRH has

the same function. According to the sequence analysis, ORF6 belongs to serine recombinase family, which includes resolvases, invertases, integrases and transposases (Smith & Thorpe, 2002), and might contribute to plasmid maintenance (Nordstrom & Austin, 1989). A putative resolvase of plasmid pPRH is phylogenetically most related to the enzyme from A. arilaitensis sharing the distinct branch (Fig. 2c). This demonstrates that, in contrast to both Rep proteins, the resolvase displays the independent patterns of evolution. Escherichia coli–Arthrobacter–Rhodococcus shuttle vectors were built using the bottom-up approach, starting with the minimal requirement for the arthrobacterial replicon taken from the cryptic plasmid pPRH. The multiple cloning site of the lacZ′ cassette

(Fig. 3) allowed using a common beta-galactosidase-based screening strategy in E. coli. The developed shuttle vectors were compatible with the pART vectors (Sandu et al., 2005). Hence, these plasmids might be used as original tools in genetic complementation studies as well as for a functional complementation-based screening in both Arthrobacter and Rhodococcus species. The successful cloning of the genes encoding the initial steps of 2-hydroxypyridine biodegradation in Arthrobacter sp. PY22 selleck inhibitor showed a potential of the developed vectors for functional screening in the nonconventional host. The cloned genes or encoded proteins were inactive in E. coli cells; hence, screening based on enzyme activities was impossible in this host. However, the pHYP1 plasmid containing genes encoding 2-hydroxypyridine catabolism could be selected using Rhodococcus or Arthrobacter as a host. It is supposed that 2-hydroxypyridine biodegradation in Arthrobacter sp. PY22 bacteria proceeds

via classical pathway by formation of 2,5-dihydroxypyridine and 2,3,6-trihydroxypyridine as intermediates (Semėnaitė et al., 2003). Implying that, the appropriate hydroxylases are expected. A sequence analysis of the cloned DNA fragment Branched chain aminotransferase showed that hpyB gene encodes a putative flavin monooxygenase belonging to the family of flavin mononucleotide (FMN)-dependent bacterial luciferases and alkanesulphonate monooxygenases, enzymes that employ reduced flavin and usually act as two-component monooxygenases in concert with NAD(P)H-dependent FMN reductases (Ellis, 2010). The hpyD gene encoding a putative NAD(P)H-dependent FMN reductase is located in close proximity to the hpyB gene. Hence, a two-component flavin monooxygenase involved in the hydroxylation of 2-hydroxypyridine ring might be expected.