FIG. 4.

Localization of NlpI. (A) NlpI was mainly located in crude membrane fraction of E. coli. Soluble, the soluble fraction of French press-ruptured bacterial cell; Membrane, the crude membrane fraction of French press-ruptured bacterial cells. (B) NlpI was mainly located in the outer membrane fraction. The crude membrane of ruptured E. coli cells was subjected to sucrose density gradient analysis to separate the inner and outer membrane fractions. Fractions corresponding to the inner membrane (IM), the intermediate density material (M), and the outer membrane (OM) were shown. The existence of NlpI and OmpA was determined by Western blot analysis with the anti-His₆ antibody and the OmpA antiserum, respectively.