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. 2002 Nov;70(11):6206–6214. doi: 10.1128/IAI.70.11.6206-6214.2002

FIG. 3.

FIG. 3.

Western analysis of cell surface proteins from strain 90-226 and its isogenic M1− and Fba− derivatives. Cell surface proteins were extracted from stationary-phase cultures of GAS, fractionated by SDS-PAGE, and transferred to nitrocellulose membranes. The phenotypes of the strains are listed above the blots. Proteins used in blots A and C were extracted from streptococci cultured to stationary phase in THY containing 25 μM of the cysteine protease inhibitor E64. Proteins for blot B were extracted from THY-grown cultures. (A and B) Blots were incubated with Fba antiserum. The arrow in panel A indicates the position of the 58-kDa band present in extracts from Fba+ strains that was not present in extracts from Fba− strains. Cell surface Fba was not detectable in cultures grown in the absence of E64. Lanes: THY, mock extraction performed with sterile culture medium; MW, molecular mass standards, with masses indicated in kilodaltons. (C) FH binding to Fba is shown. The same extracts used for blot A were transferred to a membrane, blocked, and successively incubated with 10 μg of FH/ml, FH antiserum, and a labeled secondary antibody. The arrow indicates the position of the same protein band indicated by the arrow in panel A.