Application of fusion protein 4D5 scFv-dibarnase:barstar-gold complex for studying P185HER2 receptor distribution in human cancer cells

► P185HER2 distribution in cancer cells was studied electron microscopically. ► A novel immunodetection system was used, based on the interaction of barnase with its inhibitor barstar. ► 4D5 scFv fused with two molecules of barnase and barstar-Au was used as labeling complex. ► At 4 °C P185HER2 occurs on the cell surface, at 37 °C its internalization was observed.