Fig. (3) A comparison of 20 proteins derived from S. pneumoniae using different expression and purification schemes. Manual in situ purification of E. coli, in vitro expressed proteins and column purification were compared. The purified proteins were visualized using rabbit anti-HaloTag antibody followed by a goat anti-rabbit antibody conjugated to the dye Alexa555 (upper). The purity of the proteins recovered from each strategy was examined by comparing the ratio of signal generated by an anti-E. coli antibody to that of anti-HaloTag antibody. Each well represents purification of the following protein, 1: SP_0291, 2: SP_0308, 3: SP_0321, 4: SP_0435, 5: SP_0604, 6: SP_0845, 7: SP_0954, 8: SP_0979, 9: SP_1102, 10: SP_1504, 11: SP_1572, 12: SP_1631, 13: SP_1650, 14: SP_1671, 15: SP_1699, 16: SP_1752, 17: SP_1802, 18: SP_1925, 19: SP_1959, and 20: SP_2209.