Structure and activity of glycosylated human interferon-gamma.
Structural properties and activity of recombinant human interferon-gamma (IFN-gamma) purified from Chinese hamster ovary (CHO) cells or a natural source were determined and compared with those of Escherichia coli-derived IFN-gamma. One preparation of CHO-derived IFN-gamma showed three bands, with the middle band being a doublet, in a SDS-polyacrylamide gel. The two higher-molecular-weight bands were shown to be glycosylated. Western blot analysis indicated that the three bands are IFN-gamma and lack an intact carboxyl terminus. The circular dichroic (CD) spectra showed that conformation of the CHO-derived IFN-gamma is similar in the native state, in acid, and after renaturation from acid to the E. coli-derived IFN-gamma. These results indicate that neither glycosylation nor carboxy-terminal processing affects conformational properties of the protein, as detected by CD spectroscopy. However, the antiviral activity was fourfold lower for the preparation of CHO-derived IFN-gamma than for the E. coli-derived IFN-gamma. A different preparation or a natural IFN-gamma preparation with less extensive carboxy-terminal processing showed similar conformational properties and antiviral activity to the E. coli-derived IFN-gamma. These results indicate that the carboxyl terminus, but not glycosylation, plays an important role in the antiviral activity of IFN-gamma.
D000818:Animals; D002472:Cell Transformation, Viral / Q000187:drug effects; D002942:Circular Dichroism; D006224:Cricetinae; D003412:Cricetulus; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis / Q000302:isolation & purification / Q000494:pharmacology; D008970:Molecular Weight; D010053:Ovary / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D011994:Recombinant Proteins; C046697:glycosylated gamma interferon; D007371:Interferon-gamma