X-ray crystallography and mass spectroscopy reveal that the N-lobe of human transferrin expressed in Pichia pastoris is folded correctly but is glycosylated on serine-32

The expression of the ferric form of the N-lobe of human serum transferrin in the space group P4(sub 1)2(sub 1)2 in Pichia pastoris has been undertaken. X-ray crystallography and mass spectroscopy are then used in studying the crystal structure. Results indicate that the folding pattern is identical with that of serum-derived transferrin. Spectroscopic data show that glycosylation of Ser-32 occurs with a single hexose and is the first instance of the localization of an O-linked glycan in P. pastoris.