title: Total chemical synthesis and biological activities of glycosylated and non-glycosylated forms of the chemokines CCL1 and Ser-CCL1.
abstract: CCL1 is a naturally glycosylated chemokine protein that is secreted by activated T-cells and acts as a chemoattractant for monocytes. Originally, CCL1 was identified as a 73 amino acid protein having one N-glycosylation site, and a variant 74 residue non-glycosylated form, Ser-CCL1, has also been described. There are no systematic studies of the effect of glycosylation on the biological activities of either CCL1 or Ser-CCL1. Here we report the total chemical syntheses of both N-glycosylated and non-glycosylated forms of (Ser-)CCL1, by convergent native chemical ligation. We used an N-glycan isolated from hen egg yolk together with the Nbz linker for Fmoc chemistry solid phase synthesis of the glycopeptide-(α) thioester building block. Chemotaxis assays of these glycoproteins and the corresponding non-glycosylated proteins were carried out. The results were correlated with the chemical structures of the (glyco)protein molecules. To the best of our knowledge, these are the first investigations of the effect of glycosylation on the chemotactic activity of the chemokine (Ser-)CCL1 using homogeneous N-glycosylated protein molecules of defined covalent structure.
authors.affiliation: Department of Biochemistry and Molecular Biology, Department of Chemistry, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637 (USA); Present address: Department of Chemistry, Graduate School of Science, Osaka University, 1-1, Toyonaka, Osaka 5600043 (Japan). skent@uchicago.edu, rokamoto@chem.sci.osaka-ua.ac.jp.
authors.forename: Ryo
authors.initials: R
authors.lastname: Okamoto
authors.forename: Kalyaneswar
authors.initials: K
authors.lastname: Mandal
authors.forename: Morris
authors.initials: M
authors.lastname: Ling
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Luster
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kajihara
authors.forename: Stephen B H
authors.initials: SB
authors.lastname: Kent
mesh_terms: D000595:Amino Acid Sequence; D054402:Chemokine CCL1 / Q000138:chemical synthesis* / Q000737:chemistry; D006031:Glycosylation; D008969:Molecular Sequence Data; D012694:Serine / Q000737:chemistry*
chemical_list: D054402:Chemokine CCL1; D012694:Serine
keywords: chemical protein synthesis; chemokines; glycoproteins; native chemical ligation