pGluHisTrpSerTyrGlyLeuArgProGlyNH2

pGluHisTrpSerThr... refers to a short peptide motif that begins with a pyroglutamyl (pGlu) modification at the N-terminus, followed by the amino acids histidine (His), tryptophan (Trp), serine (Ser), and threonine (Thr), with additional residues indicated by the ellipsis. The notation uses standard three-letter amino acid abbreviations, and pGlu denotes a post-translational modification in which the N-terminal glutamine or glutamate cyclizes to pyroglutamic acid. This capping is common in secreted peptides and peptide hormones.

In biological contexts, pyroglutamylation is associated with increased peptide stability, as the modification protects the N-terminus from proteolytic cleavage by aminopeptidases. It can also influence the conformational properties of the peptide and, in some cases, its affinity for receptors or other binding partners. The exact functional role of a motif like pGlu-His-Trp-Ser-Thr... depends on the broader sequence context, processing history, and the physiological system in which it occurs.

Biochemical and analytical considerations note that pyroglutamylation can affect mass and charge, factors that are relevant in experimental studies such as peptide sequencing and mass spectrometry. Synthetic versions of pGlu-containing peptides are used in research to model natural motifs, study receptor interactions, or serve as analytical standards.

See also: pyroglutamyl peptide, post-translational modification, neuropeptide, peptide sequencing.