While the characterization of the aptamer-modified
magnetic beads was performed utilizing purified PFEI-
His, the purification efficiency was demonstrated by using
complex samples. Therefore, cell lysates of E. coli expressing
different His-tagged proteins (PFEI-His, pNBE-His, and
BSTE-His) were used for aptamer-based purification. BSTE-
His was purified via 6H7 aptamer-modified magnetic beads
while pNBE-His and PFEI-His were subjected to 6H5
aptamer-based purification. The different fractions of the
purification processes were analyzed via SDS–PAGE (Fig. 5).
In the eluates BSTE-His, PFEI-His, and pNBE-His were
detected in high purity and the result of the purification
was comparable to our previously published results for
purification of PFEI-His from cell lysates utilizing Ni-NTA-
modified magnetic beads (Meng et al., 2008).