The next component of the pZM3H1 backbone, the MOB module, encodes a single mobilization protein (Orf32/MobA) sharing a low, but significant level of amino acid (aa) sequence homology with the Mob relaxases of pOCEGK02 from Oceanimonas sp. GK1 [GenBank: NC_016747] and broad-host-range plasmid pBBR1 of Bordetella bronchiseptica S87 [GenBank:X66730] (33% and 31% similarity, respectively). Detailed comparative sequence analysis of the potential Orf32/MobA relaxase revealed the presence of several conserved motifs, which permits classification of the protein into the MOBV2 group within the MOBV family . Upstream of the putative mobA (orf39) gene, an imperfect
(2 mismatches) 10-bp inverted repeat sequence was identified (5′-AAGCCCCATAGTGAGTTACGGGCCTT-3′; nt position 24,073-24,098), whose location and structure is typical for the origin of conjugal transfer (oriT) PI3K inhibitor review of MOB systems encoding MOBV type relaxases (e.g. ). Analysis of the host range of pZM3H1 To analyze the host range of the Halomonas sp. ZM3 plasmid, a mobilizable shuttle replicon pABW-ZM3H1 was constructed, containing the REP module of pZM3H1 and an E. coli-specific pMB1 (ColE1-type) replication system (see Methods for details). The obtained plasmid was introduced
via conjugation into strains representing three www.selleckchem.com/products/Decitabine.html classes of Proteobacteria: (i) Alpha- (A. tumefaciens LBA288 and P. versutus UW225), (ii) Beta- (Alcaligenes sp. LM16R), and (iii) Gammaproteobacteria (Pseudomonas spp. – strains LM5R, LM6R, LM7R, LM8R, LM11R, LM12R, LM13R, LM14R, LM15R). The plasmid was also introduced by transformation into E. coli BR825 (Gammaproteobacteria). Since the E. coli-specific system is not functional in any of the strains listed above (E. coli BR825 carries a mutation within the DNA polymerase I gene that prevents pMB1 replication), the functions required for replication of the plasmid in the tested hosts must be provided by the REP module of pZM3H1. This analysis demonstrated that pABW-ZM3H1 could
replicate P-type ATPase exclusively in two Pseudomonas strains (LM7R and LM12R), which indicates a relatively narrow host range. Characterization of the resistance modules Comparative sequence analysis revealed that a large DNA segment of pZM3H1 (10.1 kb; coordinates 7594–17,726) is highly conserved (95% nucleotide sequence identity) in the genome of Congregibacter litoralis KT71 (unfinished genome project [contig accession number – GenBank:NZ_AAOA01000001]). As shown in Figure 1, the homologous C. litoralis region differs slightly, since it contains two additional ORFs (encoding a putative DoxD-like membrane protein and a truncated transposase) that are absent in pZM3H1 (Figure 1). Further in silico sequence analysis revealed that this region of the C.