Chromatographic characterization of HSV-1 gD 268-284 and IL-6 179-185 synthetic oligopeptides by reversed-phase high-performance liquid chromatography, automated Edman degradation and mass spectrometric analysis

Mass spectrometric and chemical stability of the Asp-Pro bond in herpes simplex virus epitope peptides compared with X-Pro bonds of related sequences

The mass spectrometric analysis of the immunodominant epitope region (273-284) of herpes simplex virus type 1 (HSV-1) glycoprotein D (gD) showed a favoured fission at the Asp-Pro peptide bond. The fast atom bombardment collision induced dissociation (FAB-CID) study of closely related X-Pro peptides documented that neither the length nor the amino acid composition of the peptide has a significant influence on this preferential cleavage. At the same time the DP bond proved to be sensitive to acidic conditions in the course of peptide synthesis. These observations prompted us to compare the chemical and mass spectrometric stability of a new set of nonapeptides related to the 273-284 epitope region of gD, i.e. SALLEDPVG and SALLEXPVG peptides, where X = A, K, I, S, F, E or D, respectively. The chemical stability of these peptides during acidic hydrolysis was investigated by electrospray ionization mass spectrometry (ESI-MS) and the products were identified by ESI-MS and on-line high performance liquid chromatography-mass spectrometry (HPLC-MS). The mass spectrometric fragmentation and bond stability of the untreated peptide samples were also studied using ESI-MS and liquid secondary ion mass spectrometry (LSIMS). Both the chemical hydrolysis and the mass spectrometric fragmentation showed that the Asp-Pro bond could easily be cleaved, while the KP bond proved to be stable under both circumstances. On the other hand, the XP bond (X = A, I, S, F or E) fragmented easily under the mass spectrometric conditions, but was not sensitive to the acidolysis.

Fast atom bombardment mass spectrometry of synthetic peptides

Fast atom bombardment mass spectrometry plays a continuing and effective role in the rapid and efficient analysis of synthetic peptides. In this article, the basic principles of FAB-MS and FAB-MS/MS are reviewed, and the limitations and pitfalls of the method are discussed. The potential of the technique is illustrated by several selected applications. The molecular weight of a synthetic peptide can be readily and accurately determined by FAB-MS. The sensitivity of the FAB-MS method also makes it extremely useful for the evaluation of the purity of a peptide. FAB-MS/MS allows the elucidation of the primary structure of the target peptide, even in a mixture, and also permits the rapid identification of synthetic side products. Hence, FAB-MS and FAB-MS/MS aid in the unequivocal characterization of synthetic peptides. Furthermore, the information that is gained from the FAB analysis can help to unravel potential problems that may be associated with the synthesis.