Influence of sequential oligopeptide carriers on the bioactive structure of conjugated epitopes: comparative study of the conformation of a Herpes simplex virus glycoprotein gD-1 epitope in the free and conjugated form, and protein "built-in" crystal structure.
Synthetic carriers play an important role in immunogen presentation, due to their ability of inducing improved and specific responses to conjugated epitopes. Their influence on the bioactive conformation of the epitope, though admittedly crucial for relevant in vitro and in vivo applications, is difficult to evaluate, given the usual lack of information on the complex conformational features determined by the nature of the carrier and the mode of ligation. Using the Herpes simplex virus glycoprotein D-1 epitope (Leu(9)-Lys-Nle-Ala-Asp-Pro-Asn-Arg-Phe-Arg-Gly-Lys-Asp-Leu(22)) as a model, we have performed a detailed conformational analysis on the free epitope peptide in solution and on three constructs in which the epitope was conjugated to sequential oligopeptide carriers {Ac-[Lys-Aib-Gly](4)-OH (SOC(4))} (through either a thioether or an amide bond; Ac: acetyl) and polytuftsin oligomers {H-[Thr-Lys-Pro-Lys-Gly](4)-NH(2) (T20)}, (through a thioether bond). The analysis of the epitope conformation in the parent protein, in carrier-conjugated and free form, suggests that the beta-turn structure of the -Asp(13)-Pro-Asn-Arg(16)- segment is highly conserved and independent of the epitope form. However, small conformational variations were observed at the C-terminal part of the epitope, depending on the nature of the carrier.
Department of Chemistry, Section of Organic Chemistry and Biochemistry, University of Ioannina, 45110 Ioannina, Greece.
Dimitrios
D
Krikorian
Athanassios
A
Stavrakoudis
Nikolaos
N
Biris
Constantinos
C
Sakarellos
David
D
Andreu
Eliandre
E
de Oliveira
Gábor
G
Mezö
Zsuzsa
Z
Majer
Ferenc
F
Hudecz
Sytske
S
Welling-Wester
Manh Thong
MT
Cung
Vassilios
V
Tsikaris
D000595:Amino Acid Sequence; D001665:Binding Sites; D002942:Circular Dichroism; D003460:Crystallization; D018360:Crystallography, X-Ray; D000939:Epitopes / Q000032:analysis*; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology; D018259:Herpesvirus 1, Human / Q000737:chemistry* / Q000276:immunology; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000276:immunology; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D014270:Trifluoroethanol / Q000737:chemistry; D014867:Water / Q000737:chemistry
D000939:Epitopes; D006023:Glycoproteins; D009842:Oligopeptides; D014867:Water; D014270:Trifluoroethanol