Number of ICP4 dimers present in the B complex. (A) Schematic diagram showing EICP4 and d810. The locations of the epitopes recognized by 58S (black box) and 12CA5 (black oval) are indicated. The numbers on the top indicate the amino acid positions. (B) ICP4 DNA complexes formed between EICP4 and d810 with the probe pBend4D (Fig. 2C). The indicated proteins and monoclonal antibodies, 58S and 12CA5, were added to the indicated reactions. EICP4 and d810 formed a unique B complex (lane 5, indicated by a white star) in addition to the A and B complexes formed by EICP4 and d810. This additional B complex was supershifted by 12CA5 (lane 6, indicated by a black star). The A complexes are indicated by a white circle and a white diamond for d810 and EICP4, respectively; the B complexes are indicated by double white circles and double white diamonds for d810 and EICP4, respectively. The supershifted A and B complexes are indicated by the corresponding black circle or black diamonds. The lack of adequate resolution prevented the identification of the complexes formed in lanes 7 and 8.