Isopropyl-B-d-thiogalactopyranoside (IPTG; 1 mM final concentration,
Bangalore Genei, India) was added to log phase cultures
of E. coli BL21 DE3 pLys S cells transformed with pRSET B recombinant
plasmid for expression of His6 fusion recombinant hexon
protein. The optimum expression of protein was found out by
pilot expression. Optimum expression of protein was 4–5 h after
IPTG induction. At this point cells were harvested by centrifugation
(3000 × g for 10 min at 4 ◦C) and pellet was collected. The
pellet was resuspended in 20 ml of binding buffer (Bangalore Genie,
India; Cat No. PC-137) and after 3 cycles of freezing and thawing
the expressed protein was taken for purification. The recombinant
histidine tagged hexon protein was purified by affinity chromatography
containing Ni-NTA (Bangalore Genie, Bangalore, India; Cat
No. PC-137). The recombinant histidine tagged fusion protein was
eluted with elution buffer of different pH as per the manufacture’s
manual. The purity ofthe eluted protein was analysed on SDS-PAGE
(Fig. 4), characterized by Western Blot (Fig. 5), quantified using
spectrophotometer (Warberg and Christian, 1941) and used in both
ELISA and Dot ELISA