Amino acid sequence studies on the branched, synthetic polypeptide antigens of the immune response‐1 gene system

Abstract

Three immunogens with side chains of random amino acid sequence, poly (L Phe, l glu)-poly (DL Ala)--poly (L Lys) [(Phe, G)-A--L 223], poly (L Tyr, L Glu)-poly (DL Ala)--poly (L Lys) [(T, G)-A--L 509] and (T, G)-A-L 52, as well as two immunogens with side chains of defined amino acid sequences, GGT-A--L and TG-A--L, were sequenced using a Beckman automated sequenator. Despite the lack of a unique amino acid sequence for the amino terminus, reasonable results for the sequence studies were obtained using the Edman reaction. GGT-A--L and TG-A--L had 70% and 80% of their side chains respectively, with the desired sequence. The three compounds of random amino acid sequence were found to contain a large proportion of their A--L side chains unsubstituted. The side chains had a much greater probability of terminating in the aromatic amino acid than in the glutamic acid. The distribution of the length of side chains and their amino acid sequences was completely heterogeneous.

Specificity of H‐2‐linked Ir gene control in mice: Recognition of the core structure A–L in defined sequence analogues of (T,G)‐A–L

“…This assumption is in accordance with the amino acid sequence studies of Seaver et al for (T,G)-A--L [27]. Part of the antibodies might also be directed against the inner part of the A--L core.…”

Identification of Different Antigenic Determinants Within the Synthetic Multichain Co‐Polymer Poly(Tyr, Glu)‐PolyAla–PolyLys As Recognized by the Chicken

“…Results obtained indicate that such restrictions cannot be found, or alternatively, that restrictions are reduced to a demand for A'-terminal tyrosine [39] and, at positions 3 or 4 of the antigenic determinant, probably glutamic acid. Observations recently published, based on sequenator studies [35], and theoretical considerations on the rate of polymerization of A^-carboxyanhydride derivatives of tyrosine and Y-benzylglutamate [33], seem to support the importance of A'-terminal tyrosine. A variety of different side chains are, however, still present in a random co-polymer, even when restraints due to the predominance of A'-terminal tyrosine residues are considered [35].…”

“…Observations recently published, based on sequenator studies [35], and theoretical considerations on the rate of polymerization of A^-carboxyanhydride derivatives of tyrosine and Y-benzylglutamate [33], seem to support the importance of A'-terminal tyrosine. A variety of different side chains are, however, still present in a random co-polymer, even when restraints due to the predominance of A'-terminal tyrosine residues are considered [35]. Nevertheless, Mozes et al [21] have been able to define the sequence TTGG-as the major antigenic determinant of a batch of (T,G)-A-L: rnouse anti-(T,G)-A-L antisera could be titrated by TTGG-Pro--L and not by TGTGor TGGT-Pro-L. Studies by Cramer et al [6], demonstrating isoelectric focusing patterns of a similar degree of restrictedness of anti-(T,G)-A-L and anti-TTGG-A-L antisera and, furthermore, cotnparable to antisera raised against Fine-Spedfieities of Anti-(T,G)-A-L Antisera 309 antigens possessing a restricted number of determinants, support these findings.…”

Side Chain Distribution and Enantiomer Composition of Biodegradable Branched Polypeptides with Polylysine Backbone

“…Similar studies have been carried out on immunogenic branched polypeptides with side chains of random amino-acid sequence K-(F,E)-A, K--(Y,G)-A and of defined amino-acid sequence K-EEYA, K--YEA [20] . Despite of the complexity of these compounds, data concerning side-chain length distribution and primary structure of the branches enabled the interpretation of results from mice immunization experiments 121^.…”