FIG. 6.

Secretion of N-glycoproteins in the culture supernatant. (a) Western blot analysis of YebF-GT and ΔspYebF-GT in the culture supernatant of MC4100 cells. (b) Western blot analysis of ΔspMBP-GT fused to full-length YebF, ΔspYebF, and the spYebF signal peptide as indicated. The arrowhead indicates the YebF-ΔspMBP-GT degradation product. The supernatant (sup) and periplasmic (per) fractions were probed with anti-His antibodies or hR6P serum as indicated. Proteins were expressed in cells carrying pACYCpgl (+) or pACYCpglmut (−). All proteins were Ni-NTA affinity purified from the supernatant and periplasmic fractions. The same amount of protein was loaded in each lane. Blots were probed with anti-His or hR6P antibodies as indicated.