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A detailed mapping of the readily accessible disulfide bonds in the cortex of wool fibers
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  • Jeffrey Plowman,
  • Rachel Miller,
  • Ancy Thomas,
  • Anita Grosvenor,
  • Duane Harland,
  • Santanu Deb-Choudhury
Jeffrey Plowman
AgResearch Ltd.,
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Rachel Miller
AgResearch Ltd
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Ancy Thomas
AgResearch Ltd
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Anita Grosvenor
AgResearch Ltd
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Duane Harland
AgResearch Ltd.,
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Santanu Deb-Choudhury
AgResearch Ltd.
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Abstract

One way in which trichocyte keratin intermediate filament proteins (keratins) and keratin associated proteins (KAPs) differ from their epithelial equivalents is in their higher levels of cysteine residues. Interactions between these cysteine residues within a mammalian fiber, and the putative regular organization of interactions (i.e., types of disulfide bond) are likely important for defining fiber mechanical properties, and thus biological functionality of hairs. Here we extend a previous study of cysteine accessibility under different levels of exposure to reducing compounds to explore a finer set of levels associated with interactions between keratins and KAPs. We found that most of the cysteines in the KAPs were close to either the N- or C- terminal domains of these proteins. The most accessible cysteines in keratins were present in the head or tail domains indicating their function in readily forming intermolecular bonds with KAPs. Some of the more buried cysteines in keratins were discovered either close to or within the rod region in positions previously identified in human epithelial keratins as being involved in crosslinking between the heterodimers of the tetramer. Our present study therefore provides a deeper understanding of the accessibility of disulfides especially in keratins and thus proves that there is some specificity to the disulfide bond interactions leading to these intermolecular bonds stabilizing the fiber structure.

Peer review status:UNDER REVIEW

03 Sep 2020Submitted to PROTEINS: Structure, Function, and Bioinformatics
04 Sep 2020Assigned to Editor
04 Sep 2020Submission Checks Completed
14 Sep 2020Reviewer(s) Assigned