Fig. 2.

Localization of IglA, IglB, IglC and IglD in different biochemical fractions using detergent-based fractionation. (a–d) Immunoblots with antibodies reactive with IglA, IglB, IglC and IglD following detergent-based separation of F. novicida extracts. The amount of proteins applied to SDS-PAGE was normalized to 5 µg for each lane. The samples in the Sarkosyl-insoluble (outer-membrane) lane were distorted by the large amount of LPS present. The samples in the osmotic shock preparation (periplasm) were concentrated by filtration through a 10 kDa selective filter. (e–g) Immunoblots to detect control proteins following SDS-PAGE. MglB is a gene regulatory protein found in the cytoplasm. PdpB had previously been shown to be associated almost exclusively with the Sarkosyl-soluble fraction and the inner-membrane marker NADH oxidase (Schmerk et al., 2009b). FopA is an outer-membrane protein (Nano, 1988).