AFM_RawData_Succinyltransferase_Eskandarian

Preparation conditions and the technical setup for AFM experiments were conducted as per Eskandarian et al. 2017. Cells of M. smegmatiswildtype expressing Wag31-GFP were mixed with non-fluorescent MSMEG_3187and deposited on a PDMS-coated coverslip. WT cells were distinguished from MSMEG_3187cells by optical fluorescence microscopy. AFM measurements were made using a Dimension Icon scan head (Bruker) using ScanAsyst fluid cantilevers (Bruker) with a nominal spring constant of 0.7 N m-1in Peak Force QNM mode at a force setpoint ~1 nN and typical scan rates of 0.3 Hz. Indentation on the cell surface was estimated to be ~10 nm with a range of ~5 nm in the Z-axis. Height, peak force error, and DMT modulus channels were recorded for all scanned images in the trace and retrace directions. Images were processed using Gwyddion (Department of Nanometrology, Czech Metrology Institute – http://gwyddion.net). ImageJ was used for extracting bacterial cell profiles from height and DMT modulus images in a tabular format. A two-sided Wilcoxon rank sum U test was used to analyze the data with a continuity correction and confidence level of 95% using MatLab.