Characterization and sequence analysis of the replicator region of the novel plasmid pALC1 from Paracoccus alcaliphilus

The replicator region of a low-copy-number plasmid, pALC1. of Paracoccus al caliphilus JCM 7364 was cloned in a form of the minireplicon pALC100 (3.6 b b). The host range of the minireplicon embraces several species of genus Pa racoccus, as well as Agrobacterium tumefaciens leguminosarum and Rhodobacte r sphaeroides (all belonging to alpha -Proteoobacteria), but not Escherichi a coli. The complete nucleotide sequence of the replicator region (2276 bp) revealed the presence of one complete open reading frame coiling for the 2 8.4-kDa protein (RrpA) with similarity to replication proteins of plasmid p SW500 of Erwinia stewartii and pVS1 of Pseudomonas fluorescens The iteron-l ike region was identified upstream of the repA gene and consisted of two cl usters, of repeated sequences (17 bp long) separated by a putative DnaA box . Analysis of the predicted amino acid sequence of two adjacent incomplete ORFs suggests the localization of repA between genes involved in conjugatio n (traG) and partitioning (parA) within the pALC1 genome. (C) 2001 Academic Press.