title: Noncovalent PEGylation via Lectin-Glycopolymer Interactions.
abstract: PEGylation, the covalent modification of proteins with polyethylene glycol, is an abundantly used technique to improve the pharmacokinetics of therapeutic proteins. The drawback with this methodology is that the covalently attached PEG can impede the biological activity (e.g., reduced receptor-binding capacity). Protein therapeutics with "disposable" PEG modifiers have potential advantages over the current technology. Here, we show that a protein-polymer "Medusa complex" is formed by the combination of a hexavalent lectin with a glycopolymer. Using NMR spectroscopy, small-angle X-ray scattering (SAXS), size exclusion chromatography, and native gel electrophoresis it was demonstrated that the fucose-binding lectin RSL and a fucose-capped polyethylene glycol (Fuc-PEG) form a multimeric assembly. All of the experimental methods provided evidence of noncovalent PEGylation with a concomitant increase in molecular mass and hydrodynamic radius. The affinity of the protein-polymer complex was determined by ITC and competition experiments to be in the micromolar range, suggesting that such systems have potential biomedical applications.
authors.affiliation: School of Chemistry, National University of Ireland Galway , University Road, Galway, Ireland.|Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland.
authors.forename: Paweł M
authors.initials: PM
authors.lastname: Antonik
authors.affiliation: Department of Chemistry, Durham University , Science Laboratories, South Road, Durham DH1 3LE, United Kingdom.|Department of Polymers, Chemical Industries Research Division, National Research Centre (NRC) , El-Bohoos Street, Dokki, Cairo 12311, Egypt.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Eissa
authors.affiliation: European Molecular Biology Laboratory Grenoble Outstation , 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Round
authors.affiliation: Department of Chemistry, Durham University , Science Laboratories, South Road, Durham DH1 3LE, United Kingdom.
authors.forename: Neil R
authors.initials: NR
authors.lastname: Cameron
authors.affiliation: School of Chemistry, National University of Ireland Galway , University Road, Galway, Ireland.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Crowley
mesh_terms: D002850:Chromatography, Gel; D037102:Lectins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D011092:Polyethylene Glycols / Q000737:chemistry*; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D037102:Lectins; C027112:fucose-binding lectin; D011092:Polyethylene Glycols