Western blot analysis of Uf‐RTP1p cysteine mutants. Mutated proteins were heterologously expressed in Pichia pastoris. P, pellet; S, culture supernatant; wt, wild‐type Uf‐RTP1p. Uf‐RTP1p cysteine residues C104, C117, C147 and C179, corresponding to the conserved cysteine residues C1, C2, C3 and C4, respectively, were replaced by serine residues. Differences in the molecular weight of the Uf‐RTP1p variants originate from altered N‐glycosylation of the mutated proteins.