Fig. 1

a Colony PCR to confirm the presence of LukS-PV gene in E. coli Rosetta (DE3) strain with T7 primers on 1% agarose gel. M: 1 kb DNA Ladder; (1) Negative control; (2) Positive control (empty pET28a); (3–7) Recombinant colonies. b Analysis of protein expression. M: Protein Marker; (1) Before induction sample; (2) induction sample after 4 h (clone 1); (3) induction sample after O/N (clone 1); (4) induction sample after 4 h (clone 2); (5) induction sample after O/N (clone 2); (6) induction sample after 4 h (clone 3); (7) induction sample after O/N (clone 3). c Protein purification using Ni–NTA affinity chromatography: M: Protein marker; (1) Lysate sample; (2) Ni–NTA flow through the sample; (3) Washing samples; (4–8) Eluted samples. d Analysis and confirmation of recombinant proteins purified in Rosetta (DE3) strain using Western blotting with anti-histidine antibody. M: Protein Marker; (1) Positive control (recombinant protein with His6-Tag); (2) Negative control; (3) Purified LukS-PV protein samples under denaturing conditions