Based on these results, we conclude see more that BoaA is a well-conserved gene product shared by B. mallei and B. pseudomallei. Table 2 Percent identity shared by boaA and boaB gene products BoaA (Bm ATCC23344) BoaA (Bm NCTC10247) BoaA (Bp K96243) BoaA (Bp DD503) BoaA (Bp 1710b) BoaB (Bp K96243) BoaB (Bp DD503) BoaB (Bp 1710b) BoaA (Bm ATCC23344) 100 BoaA (Bm NCTC10247) 86.9 100 BoaA (Bp K96243) 92.7 89.2 100 BoaA (Bp DD503) 94.4 82.2 90.6 100 BoaA (Bp 1710b) 90.4 83.1 92.4 93.6 100 BoaB (Bp K96243) 64 60 65 63.9 63.9 100 BoaB (Bp
DD503) 62 60.8 62.9 61.9 62.2 96.7 100 BoaB (Bp 1710b) 62.2 60.9 63.2 62.1 62.4 97 99.7 100 Bm = B. mallei Bp = B. pseudomallei Identification of a B. pseudomallei-specific gene encoding a putative autotransporter adhesin that resembles BoaA Further analysis of the annotated genomic sequence of B. pseudomallei K96243 identified the ORF locus tag number BPSL1705 as specifying a second Oca-like protein that is ~60% identical to BoaA. The last 776 aa of BPSL1705 and BoaA are 82.5% identical (Fig 1) and the very last 93 residues, which encompass
the predicted C-terminal OM-anchoring domain and α-helical region of the molecules, were found to be particularly well-conserved (94.7% identity, Fig 1 and 2). The BPSL1705 ORF is predicted to encode a protein of 148-kDa which, as depicted in Fig 1C, possesses many LY2606368 mw of the structural features observed in BoaA including two sets of β-roll AIG motifs with the consensus xxG(S/A)(V/I)AIGxx(N/A)xAx and several SLST repeats. This high level of sequence and structural similarity between BPSL1705 and BoaA prompted
us to designate this B. pseudomallei K96243 gene product BoaB. Figure 2 Sequence comparison of boaA and boaB gene products. The last 93 residues of selected boaA and boaB gene products are shown with the Cyclin-dependent kinase 3 positions of the aa defining these regions in parentheses. Perfectly conserved aa are shown in black text over white background. Residues unique to BoaA proteins are shown in blue text over a yellow background. Residues unique to BoaB proteins are shown in white text over a blue background. Bm = B. mallei, Bp = B. pseudomallei. The boaB gene was sequenced from B. pseudomallei DD503 and was predicted to encode a protein that is 96.7% identical to BoaB of B. pseudomallei K96243. Database searches using NCBI genomic BLAST revealed that the genomes of at least 10 more B. pseudomallei strains contain the gene. Overall, the BoaB proteins are highly-conserved (90-99% identity) and characteristics of the ORF from selected strains are shown in Tables 1 and 2 and Fig 2 for comparison purposes. Importantly, database searches also revealed that none of the B. mallei isolates available through the NCBI genomic BLAST service have a boaB gene. Taken together, these results indicate that BoaB is a highly-conserved B. pseudomallei-specific molecule. Expression of the Burkholderia BoaA and BoaB proteins in E.