Immunogenic peptides corresponding to the dominant antigenic region alanine-597 to cysteine-619 in the transmembrane protein of simian immunodeficiency virus have a propensity to fold in aqueous solution

• Published in: Biochemistry (Easton) Vol. 31; no. 5; pp. 1458 - 1463
• Main Authors: Dyson, H. Jane, Norrby, Erling, Hoey, Kenway, Parks, D. Elliot, Lerner, Richard A, Wright, Peter E
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 11.02.1992
• Subjects: AIDS/HIV; alanine; Alanine - chemistry; Alanine - immunology; Amino Acid Sequence; Animals; Antibody Specificity; Antigenic determinants, haptens, artificial antigens; Antigens; Biological and medical sciences; Cross Reactions; cysteine; Cysteine - chemistry; Cysteine - immunology; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunodominant Epitopes - chemistry; Immunodominant Epitopes - immunology; Macaca; Magnetic Resonance Spectroscopy; Mice; Molecular immunology; Molecular Sequence Data; Peptide Fragments - immunology; Protein Conformation; Rabbits; Simian Immunodeficiency Virus - chemistry; Simian Immunodeficiency Virus - immunology; Solutions; Viral Envelope Proteins - chemistry; Viral Envelope Proteins - immunology; Virus; Antigen; Transmembrane protein; Synthetic product; Peptides; Retroviridae; Lentivirinae; NMR spectrometry; Simian immunodeficiency virus; Conformation
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi00120a024

Two synthetic peptides corresponding to the N- and C-terminal halves of a 23 amino acid sequence representing an immunodominant domain of the simian immunodeficiency virus of macaque origin (SIVmac) were examined for conformational preferences in aqueous solution by proton nuclear magnetic resonance methods. The two constituent peptides, termed A12-7 (Ala597-Ile-Glu-Lys-Tyr-Leu-Glu-Asp-Gln-Ala-Gln607) and A12-9 (Leu608-Asn-Ala-Trp-Gly-Cys-Ala-Phe-Arg-Gln-Val-Ser619), were found to contain a considerable conformational preference for states in which the backbone phi and psi angles populate the alpha region of the Ramachandran plot. Further, for peptide A12-9, the types and intensities of the nuclear Overhauser effect (NOE) connectivities between protons in the polypeptide backbone suggest that these states appear to include helical turns. The temperature dependence of the amide proton chemical shifts indicates that some degree of intramolecular hydrogen bonding occurs in these peptides. These results are consistent with a model in which immunogenic peptides which induce antibodies reactive with the intact protein from which the peptide sequence was derived contain conformational preferences in water solution for states other than the extended-chain forms typically found in "random coil" peptides.