A characteristic feature of high molecular weight (HMW) subunits, as with many gluten proteins, is their large repetitive central domain. This consists of tandem and interspersed repeats based on two or three consensus motifs: a nonapeptide (Gly . T yr .T yr .Pro .Thr . S er .Pro/Leu. Gln. Gln), a hexapeptide (Pro .Gly . Gln. Gly . Gln. Gln) and, in the x-type subunits only, a tripeptide (Gly.Gln.Gln). Secondary structure prediction and spectroscopic studies of purified HMW subunits and short synthetic peptides based on the consensus repeat motifs have indicated that in solution the repetitive domain forms a loose spiral consisting of regularly repeated preverse turns’”. In the solid state numerous non-covalent intermolecular interactions exist. We have used Fourier-transform infrared spectroscopy to study perfect repeat peptides with different lengths in order to understand how this affects the molecular structures.