The signals from the OspA:mRFP1 fusion proteins were quantified by densitometry of digital fluorometric images and normalized to both OspA and FlaB signals. Analysis of the untreated whole cell lysates (lanes labeled pK- in Figure 4A and Additional File 2-Figure S1) was also used to assess OspA:mRFP1 fusion lipoprotein stability. The OspA:mRFP1 fusion protein signals were normalized to the FlaB signals, and expression/in vivo stability levels were calculated in percent compared to OspA28:mRFP1. In additional blots, an OspA20:mRFP1 sample was included on each blot to normalize between individual replicates (not shown). Localization NVP-BSK805 of proteins to the IM

or OM was assessed by Western immunoblots of PC and OM membrane fractions, using OspA and OppAIV as membrane-specific controls and normalization standards (Figure 4C and Additional File 2-Figure selleck products S2). Note that the PC fraction selleck kinase inhibitor contains both protoplasmic cylinders and whole cells [4, 16], which explains the significant presence of OM proteins such as OspA in the PC fraction. The specific formulas used to calculate both the percentage of surface-localized protein and the OM/PC distribution ratios are described in the Materials & Methods section.

Figure 4 Phenotypical analysis of select OspA:mRFP1 fusion mutants. Representative Western blots of select mutants are shown (see Additional File 2-Figures S1 and S2 for full data set). Mutant-specific amino acid sequences are listed in single letter code above the blots. OspA28:mRFP1 and OspA20:mRFP1 (ED) were included as controls. (A) Protein expression and protease accessibility. Whole cell lysates of B. burgdorferi expressing mutant OspA:mRFP1 fusions from an identical

Morin Hydrate P flaB promoter (Figure 1) were obtained before (-) or after (+) in situ treatment with proteinase K (pK). A polyclonal antiserum against mRFP1 was used to detect the OspA:mRFP1 fusions. Constitutively expressed periplasmic FlaB was used as a control for loading (to normalize signals within samples) as well as for subsurface localization (negative control). OspA served as a surface control. Untreated (-pK) samples were used to assess protein expression/in vivo stability of OspA:mRFP1 fusions. (B) Distribution of proteins to inner or outer membranes. Protoplasmic cylinder (PC) and outer membrane vesicle (OM) fractions from B. burgdorferi expressing mutant OspA:mRFP1 fusions were probed with a polyclonal antiserum against mRFP1 to detect the OspA:mRFP1 fusions. IM-localized lipoprotein OppAIV was used as a PC-specific control. Surface lipoprotein OspA was used as an outer membrane control. Note that the PC fraction also contains intact cells, i.e. also contains OM proteins.