Phage binding specificity towards RhoQ63L compared to wild-type Rho. A: Ten monoclonal phages from E. coli supernatant were analyzed for binding to GST (grey columns), GST-RhoB (white columns) and GST-RhoBQ63L (black columns) protein immobilized on an ELISA plate. Bound phages were detected with horseradish peroxydase-labeled anti-M13 using TMB as substrate. Helper phage was used as a control. Results are expressed as absorbance at 480 nm. Insert: ratio of absorbance of binding to RhoBQ63L to absorbance of binding to RhoB. B: Selectivity of C1 phages on WT and activated Q63L form of Rho. 1010 clones of C1 (black columns) and control (white columns) phage were analyzed for binding to GST-RhoA, RhoB and RhoC, both wild type (WT) and Q63L forms, immobilized on a glutathione ELISA plate. Bound phages were detected with horseradish peroxydase-labeled anti-M13 using TMB as substrate. Results are expressed as absorbance at 480 nm. Concentrations of GST-Rho proteins in each well were monitored by anti-GST (not shown). The graph is representative for 3 experiments, and each binding assay was performed in duplicate.