rHaa86
The full length gene of 1.7 kb size of Bm86 orthologue of
Hyalomma anatolicum anatolicum (Haa86) cloned in the
cloning vector pET 32a and transformed in Escherichia
coli BL21(DE3)PLysS strain was available in the Entomology
laboratory, Division of Parasitology. The clones
were revived by sub-culturing in Luria Bartani (LB) broth
supplemented with ampicilline (100 lg/ml) and chloramphanicol
(34 lg/ml). For mass scale production of desired
protein, freshly grown overnight cultures were inoculated
in LB medium (1,000 ml) and incubated at 37 C with
shaking. When the OD reached at 0.5–0.6, the cells were
induced with 1 mM isopropyl-b-D-thioglactopyranoside
(IPTG) and incubated further with shaking. Bacterial cells
were harvested by centrifugation and stored at -20 C. To
purify the expressed protein, the cell pellet was resuspended
in lysis buffer (containing urea, Tris–Cl and
NaH2PO4) and mixed by vortexing. To enhance the lysis of
cells the suspension was stirred for 2 h at 22 C in the
shaking incubator at 220 rpm and sonicated at 10 lm for
5–6 times for 45 s each after 1 min rest. The cell lysate was
obtained by centrifugation and stored at -20 C. The
lysate containing the solubilized protein was subjected to
purification by nickel-nitrilotriacetic acid (Ni–NTA) agarose
resin (Qiagen, Germany). The level of recombinant
protein present in fractions collected during elution was
confirmed by SDS-PAGE. The fractions were pooled and
dialyzed using 7,000 Da cut-off dialysis membrane (Pierce,
UK) against decreasing strength of urea and finally in PBS
(pH 7.2), is to remove the urea and re-nature/refold the
protein. The resultant buffer containing recombinant
rHaa86 was subjected to ultra filtration using 50 kDa cut
off ultra filter (Pall life sciences). The protein was resolved
in SDS-PAGE (12 % gel) along with bovine serum albumin
(BSA) in the concentrations of 1–10 lg per 20 ll of
buffer. The band thickness of protein sample matching with
a particular concentration of BSA was used to calculate the
concentration of the rHaa86. The protein sample was
labeled, mixed with cocktail of protease inhibitors (Amresco,
USA) and stored at -20 C.