Publication detail

Helical twist direction in the macrofibrils of keratin fibres is left handed

HARLAND, D.P., NOVOTNÁ, V., RICHENA, M., VELAMOOR, S., BOSTINA, M., MCKINNON, A.J.

Original Title

Helical twist direction in the macrofibrils of keratin fibres is left handed

Type

journal article in Web of Science

Language

English

Original Abstract

Macrofibrils, the main structural features within the cortical cells of mammalian hair shafts, are long composite bundles of keratin intermediate filaments (KIFs) embedded in a matrix of keratin-associated proteins. The KIFs can be helically arranged around the macrofibril central axis, making a cylinder within which KIF helical angle relative to macrofibril axis increases approximately linearly from macrofibril centre to edge. Mesophase-based self-assembly has been implicated in the early formation of macrofibrils, which first appear as liquid-crystal tactoids in the bulb of hair follicles. Formation appears to be driven initially by interactions between pre-keratinized KIFs. Differences in the nature of these KIF-KIF interactions could result in all macrofibrils being internally twisted in a single handedness, or a 50:50 mixture of handedness within each cortical cell. We data-mined 41 electron tomograms containing three-dimensional macrofibril data from previously published studies of hair and wool. In all 644 macrofibrils examined we found that within each tomogram all macrofibrils had the same handedness. We concluded that earlier reports of left- and right-handed macrofibrils were due to artefacts of imaging or data processing. A handedness marker was used to confirm (using re-imaged sections from earlier studies) that, in both human and sheep, all macrofibrils are left-handed around the macrofibril axis. We conclude that this state is universal within mammalian hair. This also supports the conclusion that the origin of macrofibril twist is the expression of chiral twisting forces between adjacent KIFs, rather than mesophase splay and bending forces relaxing to twisting forces acting within a confined space.

Keywords

Hair, Wool, Orthocortex, Double-twist, Electron tomography, Data mining, DNA origami

Authors

HARLAND, D.P., NOVOTNÁ, V., RICHENA, M., VELAMOOR, S., BOSTINA, M., MCKINNON, A.J.

Released

3. 6. 2019

ISBN

1047-8477

Periodical

JOURNAL OF STRUCTURAL BIOLOGY

Year of study

206

Number

3

State

United States of America

Pages from

345

Pages to

348

Pages count

4

URL

https://www.sciencedirect.com/science/article/pii/S1047847719300735?via%3Dihub

BibTex

@article{BUT157526,
  author="Veronika {Novotná}",
  title="Helical twist direction in the macrofibrils of keratin fibres is left handed",
  journal="JOURNAL OF STRUCTURAL BIOLOGY",
  year="2019",
  volume="206",
  number="3",
  pages="345--348",
  issn="1047-8477",
  url="https://www.sciencedirect.com/science/article/pii/S1047847719300735?via%3Dihub"
}