Western blot of formaldehyde-cross-linked Y. pestis strains probed with HmsF antisera. (a) Y. pestis KIM6+ (Hms+), KIM6-2116 (ΔhmsF) and KIM6-2116(pBADhmsF) (hmsF++). Samples were cross-linked (X), not cross-linked (UX), or cross-linked and then reversed (XR). The grey arrow points to the HmsF monomer band. (b) Y. pestis KIM6+ (Hms+), KIM6-2115 (ΔhmsH) and KIM6-2115(pNPM22) (hmsH++). Except for lane 1, all samples were cross-linked. The HmsF monomer is not shown in (b). Black arrows in both panels point to the cross-linked complexes containing HmsF. Molecular masses of protein standards are shown within the range of 250–64 kDa. For (b), only the location of the 148 kDa standard is shown.