Fig 4. May1 is a member of the pepsin-like aspartyl peptidase family with optimal expression and activity at acidic pH.

(A) The domain architecture of May1. The catalytic aspartic acids are indicated by stars. (B) pH titration of May1 activity using IQ-2. Averages and standard deviation (S.D.) of triplicates are shown. (C) Immunoblot detection of May1 tagged with a CBP-2xFLAG tag in supernatants after culturing in YNB for different lengths of time. (D) Activity against IQ-2 in conditioned media from wild type C. neoformans grown in unbuffered or pH 6.5 buffered YNB. All samples were adjusted to pH 4.5 prior to being assayed. Columns represent mean ± S.D.