Conformational studies of a short linear peptide corresponding to a major conserved neutralizing epitope of human respiratory syncytial virus fusion glycoprotein.
The conformational properties of a 21-residue peptide, corresponding to amino acids 255 to 275 (F255-275) of the human respiratory syncytial virus fusion (F) glycoprotein have been studied by CD and nmr spectroscopy. This peptide includes residues 262, 268, and 272 of the F polypeptide that are essential for integrity of most epitopes that mapped into a major antigenic site of the F molecule. CD data indicate that F255-275 adopts a random coil conformation in aqueous solution at low peptide concentrations. However, as the concentration of peptide is increased, a higher percentage of peptide molecules adopts an organized structure. This effect can be more easily observed when trifluoroethanol (30%) is added to peptide solutions, giving rise to CD spectra that resemble those of alpha-helix structures. These conformational changes were confirmed by nmr spectroscopy. The nuclear Overhauser effects observed in 30% trifluoroethanol/ water together with the conformational H alpha chemical shift data allowed us to propose a structural model of helix-loop-helix for the peptide in solution. In addition, these helical regions contain the amino acid residues essential for epitope integrity in the native F molecule. These results give new insights into the antigenic structure of the respiratory syncytical virus F glycoprotein.
Toiron
C
C
Instituto de Estructura de la Materia CSIC, Madrid, Spain.
López
J A
JA
Rivas
G
G
Andreu
D
D
Melero
J A
JA
Bruix
M
M
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D000939:Epitopes / Q000737:chemistry / Q000235:genetics; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D011487:Protein Conformation; D018113:Respiratory Syncytial Virus, Human / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D014760:Viral Fusion Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology
D000939:Epitopes; D006023:Glycoproteins; D010446:Peptide Fragments; D014760:Viral Fusion Proteins