Binding Dynamics of CXC Chemokine

S. aureus (ATCC 25923) was cultured in the brain heart infusion medium to mid-logarithmic phase and then washed twice with buffer A (20 mM Tris-HCl, pH 7.5 at 25 °C). The washed bacteria were incubated with 5 µM recombinant grass carp CXCL20b or BSA for 15 min at 37 °C. Before imaging, we washed the bacteria twice with deionized water, transferred the cells to mica disks, and dried the disks overnight at 25 °C. AFM assay was carried out as previously described. AFM images were recorded on a Veeco Mulitmode AFM with NanoScope III controller operating in contact mode [43 (link)]. The data were analyzed with NanoScope Analysis software v.1.40 (Veeco, Santa Barbara, CA, USA). Scans were acquired at 25 °C at 1.0 Hz and 256 samples per line resolution.