No φC31 plaques were selleck kinase inhibitor observed on the Δpmt mutant carrying the cloned Rv1002c gene for PmtMtu [IB25(pBL9)], whereas they could be observed when the

Δpmt mutant carried an equivalent construct with the S. coelicolor pmt gene also under the control of PtipA [IB25(pBL12); Fig. 4a, plates 3 and 4; Table S2]. To explain this observation, we hypothesized that perhaps PmtMtu was functional, but failed to recognize the φC31 receptor. Therefore, plasmids pBL9 and pBL12 carrying the cloned genes for PmtMtu and PmtSco were also introduced into the S. coelicolor Δpmt mutant IB25 expressing the apa gene (from pBL1), and Apa produced by these strains was analyzed; only pBL12 carrying the gene for PmtSco complemented the ability to glycosylate the Apa protein (Fig. 4b and c, lane 3),

whereas pBL9 did not (Fig. 4b and c, lane 4). Again a few degradation products were observed, and these were more apparent when Apa was not glycosylated, which is consistent with the notion that protection from degradation might be one of the functions for protein glycosylation. These results mean that the PmtMtu enzyme learn more is unable to complement Pmt activity in the S. coelicolor mutant, even when the glycosylation target is Apa, a protein that, unlike the φC31 receptor, is normally recognized by PmtMtu. One possibility to explain these results is that PmtMtu is not being correctly localized to the S. coelicolor membrane, unlike PmtSco. To test this, both PmtSco and PmtMtu were tagged at the C-terminus with a hemagglutinin

epitope, to allow their identification using commercial anti-hemagglutinin antibodies, and cloned under the control of the PtipA promoter (pB14 and pB15, respectively; Table 1). Both plasmids were introduced into the Δpmt mutant IB25, and after induction of the cultures with thiostrepton, mycelium was harvested and subject many to fractionation, and the cytoplasmic and membrane fractions were analyzed by Western blot using anti-hemagglutinin antibodies. Hemagglutinin-tagged PmtSco could only be found in the membrane fraction (Fig. 5, lane 1) and not in the cytoplasmic fraction (Fig. 5, lane 2), meaning that the hemagglutinin tag did not affect its correct localization. In addition, the hemagglutinin-tagged PmtSco was shown to complement the Δpmt mutant IB25 for the ability to form plaques when infected with φC31 (data not shown). These results show that the hemagglutinin tag did not affect either the correct localization or the functionality of PmtSco. Hemagglutinin-tagged PmtMtu was also found only in the membrane fraction (Fig. 5, lane 3) and not in the cytoplasmic fraction (Fig.