Figure 4.

Some of the repeats identified in the silk proteins in the chironomid larvae and in the larvae of Hymenoptera. Repeats encoded by the BR genes of Chironomus contain a constant region C and the SR region composed of 4 subrepeats.⁷⁴ Smaller silk proteins, such as sp185/220 are composed of degenerate repeats.⁷⁵ The Cotesia silk protein contains the dipeptide repeat Asn (sometimes Gly, Glu or Tyr): Ser/Ala in a conserved 28 amino acid repeat.⁶² Residues conserved in all repeats of the respective protein are highlighted grey. The primary sequence of the coiled coil silk proteins (examples from Apis melifera are shown) have heptad repeats characteristic of coiled coil proteins in the seqeunce HPPHPPP where H = generally hydrophobic residues and P = generally polar or charged residues.⁶⁶ The initial residue of the heptad repeats is shown in boldface.