FIG. 5.

SDS-PAGE of S-proteins derived from S-layered cell wall fragments of PV72/p6 (lanes a, c, e, and g) and PV72/p2 (lanes b, d, f, and h) by guanidine hydrochloride extraction and their reassembly products either on hot SDS-treated peptidoglycan-containing sacculi (lanes a, b, e, and f) or alone (lanes c, d, g, and h). (a) Pellets after incubation with MVs; (b) controls (pellets incubated in buffer). The darkest-staining bands in all lanes are the S-proteins. About 10% of the S-layer protein was detected in the clear supernatants after centrifugation of the suspension (lanes with prime symbols). The amount of S-layer protein detected in the supernatant was independent of the incubation in buffer or the use of MVs (i.e., 10% is the usual amount which is solubilized if assembled S-layer material is incubated in buffer under neutral pH conditions). It is clear that the MVs are not digesting any of the S-protein reassemblies. MWM, molecular weight markers.