title: Effect of distal sugar and interglycosidic linkage of disaccharides on the activity of proline rich antimicrobial glycopeptides.
abstract: The effect of glycosylation on protein structure and function depends on a variety of intrinsic factors including glycan chain length. We have analyzed the effect of distal sugar and interglycosidic linkage of disaccharides on the properties of proline-rich antimicrobial glycopeptides, formaecin I and drosocin. Their glycosylated analogs-bearing lactose, maltose and cellobiose, as a glycan side chain on their conserved threonine residue, were synthesized where these disaccharides possess identical proximal sugar and vary in the nature of distal sugar and/or interglycosidic linkage. The structural and functional properties of these disaccharide-containing formaecin I and drosocin analogs were compared with their corresponding monoglycosylated forms, β-D-glucosyl-formaecin I and β-D-glucosyl-drosocin, respectively. We observed neither major secondary structural alterations studied by circular dichroism nor substantial differences in the toxicity with mammalian cells among all of these analogs. The comparative analyses of antibacterial activities of these analogs of formaecin I and drosocin displayed that β-D-maltosyl-formaecin I and β-D-maltosyl-drosocin were more potent than that of respective β-D-Glc-analog, β-D-cellobiosyl-analog and β-D-lactosyl-analog. Despite the differences in their antibacterial activity, all the analogs exhibited comparable binding affinity to DnaK that has been reported as one of the targets for proline-rich class of antibacterial peptides. The comparative-quantitative internalization studies of differentially active analogs revealed the differences in their uptake into bacterial cells. Our results exhibit that the sugar chain length as well as interglycosidic linkage of disaccharide may influence the antibacterial activity of glycosylated analogs of proline-rich antimicrobial peptides and the magnitude of variation in antibacterial activity depends on the peptide sequence.
authors.affiliation: Structural Biology Unit, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110 067, India.
authors.forename: Deepti S
authors.initials: DS
authors.lastname: Lele
authors.affiliation: Structural Biology Unit, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110 067, India.
authors.forename: Rohini
authors.initials: R
authors.lastname: Dwivedi
authors.affiliation: Structural Biology Unit, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110 067, India.
authors.forename: Saroj
authors.initials: S
authors.lastname: Kumari
authors.affiliation: Structural Biology Unit, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110 067, India.
authors.forename: Kanwal J
authors.initials: KJ
authors.lastname: Kaur
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D002236:Carbohydrate Conformation; D004187:Disaccharides / Q000737:chemistry; D029721:Drosophila Proteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D015195:Drug Design; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D006020:Glycopeptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D006031:Glycosylation; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism; D019476:Insect Proteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008970:Molecular Weight; D011392:Proline / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012486:Salmonella typhimurium / Q000187:drug effects / Q000254:growth & development; D060327:Solid-Phase Synthesis Techniques
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D004187:Disaccharides; D029721:Drosophila Proteins; D029968:Escherichia coli Proteins; D006020:Glycopeptides; D006023:Glycoproteins; D018840:HSP70 Heat-Shock Proteins; D019476:Insect Proteins; C111162:formaecin 1 protein, Myrmecia gulosa; C082117:drosocin; D011392:Proline; C063842:dnaK protein, E coli
keywords: antibacterial peptide; disaccharide; glycosylation; proline-rich