Title :
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
Abstract :
- The ferric form of the N-lobe of human serum transferrin ( Fe(III )- hTF /2N) has been expressed at high levels in Pichia pastoris
- The Fe(III )- hTF /2N was crystallized in the space group P41212, and X-ray crystallography was used to solve the structure of the recombinant protein at 2.5 A resolution
- This represents only the second P. pastoris-derived protein structure determined to date, and allows the comparison of the structures of recombinant Fe(III )- hTF /2N expressed in P. pastoris and mammalian cells with serum-derived transferrin
- The polypeptide folding pattern is essentially identical in all of the three proteins
- Mass spectroscopic analyses of P. pastoris- hTF /2N and proteolytically derived fragments revealed glycosylation of Ser-32 with a single hexose.
- This represents the first localization of an O-linked glycan in a P. pastoris-derived protein
- Because of its distance from the iron-binding site , glycosylation of Ser-32 should not affect the iron-binding properties of hTF /2N expressed in P. pastoris, making this an excellent expression system for the production of hTF /2N