The complete amino acid sequence of a feather keratin from emu (Dromaius novae-hollandiae)

Abstract

The complete amino acid sequence of one of the two major components comprising the rachis and calamus of emu (D. novae-hollandiae) feather keratin has been determined. The molecule consists of 102 amino acids and has a molecular weight (in the S-carboxymethyl form) of 10,459. The half-cystine residues are located towards either end of the molecule. There is an insoluble tryptic peptide of 65 residues, T3, in which the hydrophobic residues Val, Leu, and He are preferentially placed and this section also contains most of the Ser and Gly residues of the molecule. It is the T3 section which contains the crystalline part of the molecule. Comparison of the sequence with peptides isolated by Schroeder et al. (1957) from calamus from turkey feather suggests that the T3 section in both feathers could be very similar. The proline residues are not regularly distributed. The N-terminal sequence, NAc-Ser-SCMCys-Tyr is the same as that found previously in goose (Anser domesticus) feather calamus. © 1973 CSIRO.