Glycosylation‐Dependent Stability of Human Pentraxin‐2 Revealed by Surface‐Induced Dissociation and Ion Mobility Mass Spectrometry

Abstract

Abstract Pentraxin‐2 (PTX‐2), also known as Serum Amyloid P component, functions as an immunoregulatory glycoprotein and plays a crucial role in fibrotic diseases such as idiopathic pulmonary fibrosis (IPF). Desialylation of PTX‐2 has recently been associated with reduced bioactivity and diminished inhibition of fibrocyte differentiation in IPF patients. Each monomer in the naturally assembled pentameric complex is N‐glycosylated, predominantly featuring terminal sialic acids on biantennary glycans. However, the influence of these glycoforms on PTX‐2′s mechanism of action (MoA) and conformational properties has not been comprehensively investigated. In this study, we demonstrate the combined application of surface‐induced dissociation (SID) and ion‐mobility mass spectrometry (IM‐MS) to assess the impact of specific glyco‐engineered PTX‐2 variants on the stability of its pentameric and decameric complexes. We further explore the effect of individual monomer glycosylation on complex stability. Our results reveal that high levels of terminal sialylation significantly enhance complex stability, whereas desialylation and mannosylation reduce the stability of both pentameric and decameric PTX‐2 forms. Regarding the stability of single PTX‐2 monomers ejected from the pentamer, in contrast, we found that desialylated and highly mannosylated glycans contribute to the individual monomer stability.