title: Characterization of the exocuticle a-layer proteins of wool.
abstract: The outermost protein layer of wool cuticle cells is known as the exocuticle a-layer. This layer is a resistant barrier to the degradation of the fibre and, as a result, little is known of its proteinaceous composition. Merino wool fibres were subjected to both proteolytic and chemical digestion and the resulting material was found by transmission electron microscopy to be highly enriched in a-layer. Amino acid analysis revealed a high cysteine and glycine content, with a close, but not exact, match to the Allwörden membrane. Subsequent digestion of the a-layer preparation by 2-nitro-5-thiocyano-benzoic acid produced a large number of short peptides, and analysis by mass spectrometry revealed peptides with strong homologies to cuticular ultra-high sulphur proteins of sheep wool and cuticular ultra-high and high-sulphur proteins of human hair, thus supporting other evidence for the presence of these sulphur-rich proteins in the a-layer.
authors.affiliation: AgResearch, Christchurch, New Zealand.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Bringans
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Plowman
authors.forename: Jolon M
authors.initials: JM
authors.lastname: Dyer
authors.forename: Stefan
authors.initials: S
authors.lastname: Clerens
authors.forename: James A
authors.initials: JA
authors.lastname: Vernon
authors.forename: Warren G
authors.initials: WG
authors.lastname: Bryson
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D055233:Cornified Envelope Proline-Rich Proteins; D003545:Cysteine / Q000032:analysis; D005998:Glycine / Q000032:analysis; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000032:analysis*; D011498:Protein Precursors / Q000032:analysis*; D012756:Sheep; D014935:Wool / Q000737:chemistry* / Q000166:cytology / Q000648:ultrastructure
chemical_list: D000596:Amino Acids; D055233:Cornified Envelope Proline-Rich Proteins; D008565:Membrane Proteins; D011498:Protein Precursors; C064554:loricrin; C032253:involucrin; D003545:Cysteine; D005998:Glycine