Proteoform Profile Mapping of the Human Serum Complement Component C9 Revealing Unexpected New Features of N-, O-, and C-Glycosylation.

ABSTRACT: The human complement C9 protein (∼65 kDa) is a member of the complement pathway. It plays an essential role in the membrane attack complex (MAC), which forms a lethal pore on the cellular surface of pathogenic bacteria. Here, we charted in detail the structural microheterogeneity of C9 purified from human blood serum, using an integrative workflow combining high-resolution native mass spectrometry and (glyco)peptide-centric proteomics. The proteoform profile of C9 was acquired by high-resolution native mass spectrometry, which revealed the co-occurrence of ∼50 distinct mass spectrometry (MS) signals. Subsequent peptide-centric analysis, through proteolytic digestion of C9 and liquid chromatography (LC)-tandem mass spectrometry (MS/MS) measurements of the resulting peptide mixtures, provide

SUBMITTER: Franc V 

PROVIDER: S-EPMC5362742 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature