The Polybasic Region of the Polysialyltransferase ST8Sia-IV Binds Directly to the Neural Cell Adhesion Molecule, NCAM
| Autor: | Gaurang P. Bhide, Gerd Prehna, Karen J. Colley, Benjamin E. Ramirez |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Models Molecular Fibronectin Type III Domain Recombinant Fusion Proteins SUMO-1 Protein Gene Expression Immunoglobulin domain Biochemistry Article Protein Structure Secondary 03 medical and health sciences chemistry.chemical_compound Downregulation and upregulation Chlorocebus aethiops Escherichia coli Animals Humans Histidine Amino Acid Sequence Cloning Molecular Cell adhesion Neural Cell Adhesion Molecules chemistry.chemical_classification Binding Sites 030102 biochemistry & molecular biology biology Polysialic acid Sialyltransferases Sialic acid Cell biology Fibronectin 030104 developmental biology chemistry COS Cells biology.protein Sialic Acids Neural cell adhesion molecule Glycoprotein Peptides Oligopeptides Protein Processing Post-Translational Sequence Alignment Protein Binding |
| Popis: | Polysialic acid (polySia) is a unique post-translational modification found on a small set of mammalian glycoproteins. Composed of long chains of α2,8-linked sialic acid, this large, negatively charged polymer attenuates protein and cell adhesion and modulates signaling mediated by its carriers and proteins that interact with these carriers. PolySia is crucial for the proper development of the nervous system and is upregulated during tissue regeneration and in highly invasive cancers. Our laboratory has previously shown that the neural cell adhesion molecule, NCAM, has an acidic surface patch in its first fibronectin type III repeat (FN1) that is critical for the polysialylation of N-glycans on the adjacent immunoglobulin domain (Ig5). We have also identified a polysialyltransferase (polyST) polybasic region (PBR) that may mediate substrate recognition. However, a direct interaction between the NCAM FN1 acidic patch and the polyST PBR has yet to be demonstrated. Here, we have probed this interaction using isothermal titration calorimetry and nuclear magnetic resonance (NMR) spectroscopy. We observe direct and specific binding between FN1 and the PBR peptide that is dependent upon acidic residues in FN1 and basic residues of the PBR. NMR titration experiments verified the role of the FN1 acidic patch in the recognition of the PBR and suggest a conformational change of the Ig5-FN1 linker region following binding of the PBR to the acidic patch. Finally, mutation of residues identified by NMR titration experiments impacts NCAM polysialylation, supporting their mechanistic role in protein-specific polysialylation. |
| Databáze: | OpenAIRE |
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