Rck is a C4BP binding protein.

<p>A, FACS analysis of C4BP binding. 2×10⁸ CFU/ml of BL21(DE3) and BL21(DE3) pRck in DPBS were mock treated (DPBS only) or incubated with 10% HIS for 30 min. C4BP binding was measured by FACS using a mouse monoclonal anti-human C4BP antibody. Mean fluorescence intensity (MFI) values are indicated. Representative data of an experiment performed at least three times are shown. B, Direct binding of ¹²⁵I-labeled C4BP to Rck. 1×10⁹ CFU/ml of BL21(DE3) and BL21(DE3) pRck in GVB were incubated with ¹²⁵I-C4BP (∼ 20,000 cpm/sample). The ratio of bound to total radioactivity was then determined (% bound). Data is expressed as means of two independent experiments performed in duplicate ± SD. C, Dose-dependent and saturable binding of C4BP to Rck. Bacteria prepared as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0027546#pone-0027546-g001" target="_blank">Figure 1A</a> were incubated with increasing amounts of purified C4BP and detected by FACS as described above using a polyclonal anti-C4BP antiserum. Data is expressed as means of the MFI values acquired from three independent experiments ± SD.