Histones with carbohydrate-binding ability

FERRERO, FA; IRAZOQUI FJ

Mendoza, Argentina

Congreso; SAIB; 2022

SAIB

Histones are nuclear proteins with the ability of binding to DNA molecules. Its main function is associated with the packaging of genetic material by the formation of nucleosomes regulating gene expression. They can be classified into five families: H1, H2A, H2B, H3 and H4. Previous evidence demonstrated the presence of different types of glycans in the cell nucleus and the ability of histones to interact with glycans. Here we investigate whether histones can specifically bind to glycosidic structures. Initially, histones purified from cow thymus were successfully biotinylated for follow-up in subsequent assays. An agarose column conjugated with ε-aminocaproylgalactosamine was used in affinity chromatography to evaluate its ability to retain them. Purified cow histones were incubated with the chromatographic support and retained histones were recovered by elution with lactose. The eluated proteins reacted with streptavidin indicating that some biotinylated histone interacted with the ligand on the column and was consequently eluted with lactose. Polyacrylamide gels stained with Coomassie Brilliant Blue allowed the identification of bands with molecular weights similar to histones. Furthermore, direct interaction assays of histone recovered from affinity chromatography with glycoproteins showed a clear interaction preference for Glucosamine-Bovine Serum Albumin (GlcN-BSA). Histone-glycan interaction assays in the presence of carbohydrates showed inhibitory effect (lactose) while other sugar (GlcN) increased the binding of histones with GlcN-BSA. Similar results were observed with recombinant human histone H2A, showing an important interaction with GlcN-BSA and differential behavior in presence of carbohydrates: GlcN enhances binding and lactose shows an inhibitory effect. Taken together, these results indicate that histones have some capacity to recognize glycans, showing similar behavior to a lectin. Further studies regarding the ability of histones to interact with glycans are in development by our research group.