N-glycan structures of matrix metalloproteinase-1 derived from human fibroblasts and from HT-1080 fibrosarcoma cells

Matrix metalloproteinase-1 (MMP-1) is a collagenolytic metalloproteinase ca pable of cleaving native triple-helical forms of several collagen subtypes, as well as a number of non-collagenous substrates. The role of MMP-1 in va rious diseases affecting the connective tissue is well characterized. MMP-1 is secreted as both glycosylated and unglycosylated species, and the two f orms have been shown to be identical with respect to substrate specificity, specific activity and inhibitory profile. No function for the glycan moiet y of the enzyme has been ascribed to date. In the present study, we report on the detailed characterization of MMP-1-derived oligosaccharides. Using s trategies based on sequential exoglycosidase digestion combined with matrix -assisted laser desorption ionization-time of flight MS and electrospray ta ndem MS, we have characterized the N-glycan structures of MMP-1, derived fr om human dermal fibroblasts and from the HT-1080 fibrosarcoma cell line. MM P-1 derived from fibroblasts was found to carry mainly alpha 2,3-sialylated complex-type diantennary glycans. On the other hand, MT-1080 cells produce MMP-1 that has a heterogeneous glycosylation pattern, comprising diantenna ry glycans carrying Lewis X, LacdiNAc, sialylated LacdiNAc and GalAc beta 1 ,4(Fuc alpha 1,3)GlcNAc (LacdiNAc analogue of Lewis X) as terminal elements . We also show that, of the two potential glycosylation sites in the MMP-1 sequence, only Asn120 is used.