FIG 5 .

SLO and NADase bind in a 1:1 stoichiometry. (A) Molecular masses of NADase (47.2 kDa), SLO (64.6 kDa), and NADase + SLO (83 kDa) were determined by SEC-MALS of column elution peaks. Elution profiles are shown (solid lines) with calculated masses (circles) for each condition. (B and C) The stoichiometry of NADase-SLO binding was determined to be 1:1 by cross-linking of interacting NADase and SLO and identification of a heterodimer species by SDS-PAGE (*) (B) and MALDI-TOF mass spectrometry (C).