FIG 5.

The G⁶⁷²R mutation and the deletion of K⁸⁸³ in the cytoplasmic tail of gB^B4.1 account for enhanced fusion activity. To test which changes in gB^B4.1 are responsible for the higher fusion activity, mutations were introduced singly or in combinations into gB^Ka. Fusion activity in combination with gH^Ka was measured in cotransfected RK13 cells, and results from assays with gB^B4.1 and gH^Ka were set as 100%. Given are mean values from three independent experiments with corresponding standard deviations.