The neuropeptide galanin occurs in two conformations

The secondary structure of the six known species forms of galanin was predicted using a statistical method. In the region between positions 13 and 20 the model predicts α-helical structures in human, cow, and chicken galanin, whereas the model does not predict α-helical structures in the same region of pig, rat, and sheep galanin. Based on the different conformational states of galanin, the species forms of galanin could be divided in two groups: galanin A (= human, cow, chicken galanin) and galanin B (= pig, rat, and sheep galanin). A chemical explanation might thus be provided for the observed differences in potency between different species forms of galanin (A or B) to inhibit insulin secretion.