title: Controlled synthesis of O-glycopolypeptide polymers and their molecular recognition by lectins.
abstract: The facile synthesis of high molecular weight water-soluble O-glycopolypeptide polymers by the ring-opening polymerization of their corresponding N-carboxyanhydride (NCA) in very high yield (overall yield > 70%) is reported. The per-acetylated-O-glycosylated lysine-NCA monomers, synthesized using stable glycosyl donors and a commercially available protected amino acid in very high yield, was polymerized using commercially available amine initiators. The synthesized water-soluble glycopolypeptides were found to be α-helical in aqueous solution. However, we were able to control the secondary conformation of the glycopolypeptides (α-helix vs nonhelical structures) by polymerizing racemic amino acid glyco NCAs. We have also investigated the binding of the glycopolypeptide poly(α-manno-O-lys) with the lectin Con-A using precipitation and hemagglutination assays as well as by isothermal titration calorimetry (ITC). The ITC results clearly show that the binding process is enthalpy driven for both α-helical and nonhelical structures, with negative entropic contribution. Binding stoichiometry for the glycopolypeptide poly(α-manno-O-lys) having a nonhelical structure was slightly higher as compared to the corresponding polypeptide which adopted an α-helical structure.
authors.affiliation: CReST, Chemical Engineering Division,  National Chemical Laboratory  (CSIR), Dr. Homi Bhabha Road, Pune-411 008, India.
authors.forename: Debasis
authors.initials: D
authors.lastname: Pati
authors.forename: Ashif Y
authors.initials: AY
authors.lastname: Shaikh
authors.forename: Soumen
authors.initials: S
authors.lastname: Das
authors.forename: Pavan Kumar
authors.initials: PK
authors.lastname: Nareddy
authors.forename: Musti J
authors.initials: MJ
authors.lastname: Swamy
authors.forename: Srinivas
authors.initials: S
authors.lastname: Hotha
authors.forename: Sayam Sen
authors.initials: SS
authors.lastname: Gupta
mesh_terms: D000812:Anhydrides / Q000737:chemistry; D006020:Glycopeptides / Q000138:chemical synthesis* / Q000737:chemistry; D037102:Lectins / Q000737:chemistry*; D015394:Molecular Structure; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000812:Anhydrides; D006020:Glycopeptides; D037102:Lectins; D011108:Polymers