title: Insights on the amino acid side-chain interactions of a synthetic T-cell determinant.
abstract: The effect of single amino acid substitutions at positions 18 and 20 on the T-cell determinant (TD) character of peptide p12-26 from lambda repressor protein and on its recognition by a monoclonal antibody was studied by means of 40 synthetic peptides of a length of 15 amino acids. ELISA competition experiments showed that the identity of amino acid at position 20 is very important for antibody recognition, whereas that of amino acid at position 18 is much less important. In contrast, both Leu 18 and Ala 20 are important residues in defining the TD character of peptide p12-26. The most tolerated replacements, ordered in increasing disrupting power are: Ala 20 by Cys, Ser or Gly and Leu 18 by Ile or Val. Any other amino acid replacement completely abolishes the TD capacity of peptide p12-26. The peptides used in this study were synthesized using a multiple solid-phase peptide synthesizer newly designed. Their purity was very high as shown by amino acid sequence experiments.
authors.affiliation: Departamento de Medicina Interna, Facultad de Medicina, Universidad de Navarra, Pamplona, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Borrás-Cuesta
authors.forename: J
authors.initials: J
authors.lastname: Golvano
authors.forename: P
authors.initials: P
authors.lastname: Sarobe
authors.forename: J J
authors.initials: JJ
authors.lastname: Lasarte
authors.forename: I
authors.initials: I
authors.lastname: Prieto
authors.forename: A
authors.initials: A
authors.lastname: Szabo
authors.forename: J L
authors.initials: JL
authors.lastname: Guillaume
authors.forename: J G
authors.initials: JG
authors.lastname: Guillet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D004268:DNA-Binding Proteins; D000939:Epitopes / Q000737:chemistry*; D006825:Hybridomas / Q000276:immunology; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000276:immunology*; D012097:Repressor Proteins / Q000737:chemistry / Q000276:immunology; D013329:Structure-Activity Relationship; D013601:T-Lymphocytes / Q000276:immunology*; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D000911:Antibodies, Monoclonal; D004268:DNA-Binding Proteins; D000939:Epitopes; D010455:Peptides; D012097:Repressor Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins