Abstract Number: PB0718
Meeting: ISTH 2020 Congress
Background: Coagulation factor XIII consists of two potentially active A subunits and two protective/inhibitory B subunits (FXIII-A2B2). In plasma FXIII-B2 is in a two-fold excess over FXIII-A2. FXIII-B is a ~80 kDa glycoproteincontaining 8.5% carbohydrate on two N-glycosylation sites. Neither the structure nor the functional role of the glycans on FXIII-B has been explored.
Aims: To reveal the glycan structures linked to FXIII-B, to deglycosylate the native protein and use it for functional studies.
Methods: The asparagine linked carbohydrates were released from human FXIIII-B by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase (PNGase F) digestion under both denaturing and native conditions. The released N-linked oligosaccharides were fluorophore labeled and analyzed by capillary electrophoresis. Structural identification utilized glycan database search and exoglycosidase digestion based sequencing. The monomeric/dimeric structure of deglycosylated FXIII-B (dFXIII-B) was investigated by gel filtration. The association of native and dFXIII-B2 to FXIII-A2 were compared by surface plasmon resonance. Deglycosylated and native FXIII-B were injected into FXIII-B knock out mice and their clearance was monitored.
Results: Deglycosylation of the native protein was achieved by repeated PNGase F digestion. The total N-glycan profile of FXIII-B featured 9 individual structures, The core structure contained two N-acetyl glucosamines and three mannoses, four of them were fucosylated. Each structure contained at least one sialic acid. The elution profile of native and deglycosylated FXIII-B were similar, i.e, the absence of glycan structure did not change the dimeric structure. The equilibrium dissociation constant for the interaction of FXIII-A2 and dFXIII-B2 was one magnitude higher (2.35×10-8 M) than with the native protein (6.80×10-9 M). Deglycosylation highly accelerated the clearance of FXIIII-B2 from the circulation of FXIII-B knock out mice.
Conclusions: Characterization of the glycan moieties attached to FXIII-B is reported for the first time. The attached glycan very likely plays an important role in prolonging the persistence of FXIII-B2 and FXIII-A2B2 in the circulation.
To cite this abstract in AMA style:Hurják B, Kovács Z, Katona É, Pénzes K, Haramura G, Sadeghi F, Shemirani A, Guttman A, Muszbek L. The Glycan Structure Associated to Factor XIII Subunit B and its Functional Importance [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/the-glycan-structure-associated-to-factor-xiii-subunit-b-and-its-functional-importance/. Accessed February 27, 2024.
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