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. 2013 Aug 2;8(8):e70092. doi: 10.1371/journal.pone.0070092

Figure 5. Bacteriophage-derived depolymerase specific for KN2 capsular polysaccharides.

Figure 5

(A) Immunoblot showing depolymerzation of KN2 extracted capsular polysaccharides by purified ORF96 proteins. The extracted capsular polysaccharides alone or incubated with ORF96 proteins (10 µg) at 37°C for 6 h were separated by SDS-PAGE, transferred onto a nitrocellulose membrane and detected using rabbit anti-C1975 antiserum (1∶5000) and goat anti-rabbit IgG-HRP (1∶10 000). Lane1: Ca0507Δorf8 alone; lane2: wild-type Ca0507 alone; lane3: wild-type Ca0507 plus ORF96 proteins. (B) A spot test showing ORF96 proteins with the depolymerase activity to KN2. Purified ORF96 proteins (1 µg) was spotted on the bacterial lawn and incubated at 37°C overnight. Decapsulation of KN2 K. pneumoniae NTUH-K1790N, Ca0507, Ca0421 and C1975 was observed. K1 ref. presents the reference strain of the K1 serotype. (C) Comparison of sensitivity of phage 0507-KN2-1 and capsular polysaccharide depolymerase. Spot tests with serial titration (counter-clockwise) of phage 0507-KN2-1 (upper panels) or purified ORF96 proteins (lower panels) on KN2 strains as indicated.