glycineprolineaspartate

Glycineprolineaspartate is the name given to a tripeptide that consists of the amino acids glycine, proline, and aspartic acid linked in the sequence Gly-Pro-Asp. It can occur as a discrete tripeptide or as part of larger polypeptides formed by proteolysis or peptide synthesis.

Its structure features an N-terminal amino group from glycine and a C-terminal carboxyl group from aspartic acid. The side chains include a hydrogen on glycine, a constrained pyrrolidine ring from proline, and a negatively charged carboxylate on aspartic acid, giving the peptide a net negative charge (-1) at physiological pH. Its approximate molecular weight is around 269 Da. In aqueous solution it is hydrophilic.

Synthesis and occurrence: Synthetically, Gly-Pro-Asp can be assembled by standard peptide synthesis techniques. In natural proteins, Gly-Pro-Asp may appear as a short fragment generated by proteolytic cleavage. The presence of Asp at the C-terminus influences certain side reactions during synthesis, but a simple Gly-Pro-Asp sequence is generally manageable under common laboratory conditions.

Applications and significance: As a simple model tripeptide, Gly-Pro-Asp is used in studies of peptide conformation and dynamics, particularly to observe effects of the rigid Proline residue on backbone angles. It can also serve as a building block in peptide libraries and in the design of short peptidomimetics. There is no widely recognized unique biological function or disease association attributable specifically to this tripeptide.