Dynamic electrophoretic fingerprint (DEF) of monomeric BX08 gp120. Mobility measurements were made across a pH titration (3.0-9.0) in 0.5 pH increments) and over a range of salinities (1-200 mM NaCl), expressed as the negative log of the conductivity (pλ 2.60 to 4.28). Titrations were performed in triplicate, with three measurements made at each pH for all pλ conditions. (A) Postage stamp plot showing distribution of data collection. Each cross represents the average pH and pλ of three electrophoretic mobility measurements. (B) Contour plot of the electrophoretic fingerprint generated from the data collected in (A). Line of zero mobility (LZM), bolded, indicates the isoelectric point at the lowest pH and pλ conditions examined. Bold black lines indicate mobility changes of 0.6 μmcm/Vs. Arrows indicate the pH and pλ conditions of several relevant biological mediums. (C) Overlay of postage stamp and DEF shows data distribution includes all key features.