Figure 5.

S. aureus Eap protects the N terminus of SPIN from degradation by NSPs. The consequences of including the S. aureus-derived NSP inhibitor, Eap (14), in the SPIN–NSP proteolysis reactions were assessed using an assay format identical to that presented in Fig. 4. The presence of Eap protected the N terminus of SPIN from proteolysis by 18 μg/ml NE (A), 4.5 μg/ml CG (B), and 4.5 μg/ml PR3 (C). Importantly, although SPIN on its own inhibited MPO activity, the addition of Eap was required to fully restore SPIN function in the presence the NSPs. Bars express S.D. with n = 3, and legends are at right.