Tris 2 carboxyethyl phosphine hydrochloride disulfide reducing gel

RGD peptide was purchased from Peptides International. Peptide ligands for the anti-HIV antibody and the anti-Ebola antibody were synthesized by CPC Scientific with a purity >95%. DNP and biotin disulfides were synthesized in our laboratory (SI Appendix, Figs. S12 and S13) and reduced for 2 h before use by an immobilized (Tris[2-carboxyethyl] phosphine hydrochloride) disulfide reducing gel from Thermo Scientific (catalog number 77712) following the manufacturer’s instructions. Preparation of the solutions used in this work is described in SI Appendix. Anti-DNP antibody (mouse monoclonal IgE antibody), wild-type streptavidin, and all other chemicals were purchased from Sigma Aldrich. Anti-HIV antibody (Anti-HIV1 p17 antibody [32/1.24.89]) and all of the isotype controls were obtained from Abcam. Anti-Ebola antibody was cultured from plants as described in SI Appendix. Binding affinities of all of the three antibodies were measured by surface plasmon resonance. Thiolated streptavidin with an average of 2.5 thiols per tetramer was from ProteinMods. Ag/AgCl reference electrodes salt-bridged by 3 M KCl or 10 mM KCl were prepared as described previously (15 (link)). Full details of the cyclic voltammetry are provided in SI Appendix. The anti-Ebola antibody and the corresponding monomeric Fab fragment were prepared and purified as described in SI Appendix.