Figure 1. The phage 77 ORF104 protein binds the S. aureus DnaI ATPase domain.
(A) Domain organization of SaDnaI. The N-terminal helicase-binding domain is colored gray, the linker region is magenta, and the AAA+ domain is orange. Numbers refer to amino acid positions. AAA+ ATPase motifs are labeled: Walker-A (WA), Walker-B (WB), Sensor-I (SI), Box VII, Sensor-II (SII), and the initiator/loader specific motif (ISM). (B) SDS-PAGE analysis of amylose pull-downs between His6MBP-77ORF104 and full-length SaDnaI (with ATP). A DnaI alone control is shown. Supernatant – S/N, W1 and W2 – washes. (C) Limited trypsin proteolysis and SDS-PAGE analysis of full-length SaDnaI in the presence of 77ORF104. A ~20kDa band of SaDnaI is stabilized in the presence of 77ORF104.