Wool as a Biological Composite Structure

Zahn, Helmut; Föhles, Josef; Nlenhaus, Magdalene; Schwan, Annette; Spel, Manfred

doi:10.1021/i360076a005

Cited by 71 publications

(39 citation statements)

References 5 publications

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“…Additionally, the composite nature of keratin results in a roughly inverse relationship between the stiffness (elastic modulus) and the volume fraction of amorphous matrix (less-crystalline composite) (i.e. as the content of the amorphous keratin increases, the bulk keratin's stiffness decreases) [30,37]. This relationship between crystallinity and elastic modulus is also common to semi-crystalline synthetic polymers [38,39].…”

Section: Biopolymersmentioning

confidence: 99%

Structure and mechanical properties of selected protective systems in marine organisms

Naleway

Taylor

Porter

et al. 2016

Materials Science and Engineering: C

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Section: Biopolymersmentioning

confidence: 99%

Structure and mechanical properties of selected protective systems in marine organisms

Naleway

Taylor

Porter

et al. 2016

Materials Science and Engineering: C

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“…DTA files (Bioworks version 3.1) in ASCII format for each MS/MS spectrum were generated from the raw data for the peptide mass range of 500 -3,500, minimum ion count of 10, and minimum signal of 10 5 . The International Protein Index human database (ipi.HUMAN.v3.01, December 3, 2004, downloaded from ftp.ebi.ac.uk/pub/databases/IPI) containing 46,941 entries was used for Sequest searching.…”

Section: Lc-ms and Lc-ms/ms-peptidementioning

confidence: 99%

Proteome Analysis of Human Hair Shaft

Lee

Rice

Lee

2006

Molecular & Cellular Proteomics

112

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The human hair proteome was investigated using twodimensional LC-MS/MS. Among the 343 identified proteins, 70 were detected in high relative abundance, including keratin intermediate filament proteins, largely extractable with denaturants. Over 300 proteins were found to constitute the insoluble complex formed by transglutaminase cross-linking. The intracellular distribution of identified proteins is wide from cytoplasm to nucleus, mitochondria, ribosome, and plasma membrane. These results help rationalize ultrastructural features visible in the mature hair. Keratins and several substrates for transglutaminase were found to be posttranslationally modified by methylation and dimethylation. Evidence for ubiquitination of hair proteins was also obtained. Molecular & Cellular Proteomics 5:789 -800, 2006.Hair is synthesized in mammals by specialized follicles in the skin. In the follicles, cells undergo an intricate maturation program resulting in a hair shaft of terminally differentiated cells. In humans, a protective layer of cuticle cells surrounds the cortex, which in turn surrounds an intermittent column of medulla cells in the center of the shaft. In each of the three layers, the cells have distinctive shapes and contents (1, 2). The keratins and keratin-associated proteins (KAPs), 1 major constituents of the cortex, have been studied for many years after extraction with denaturants under reducing conditions. However, the contents of the medulla and cuticle cells have been much harder to examine because they present great difficulties in solubilization. A major advance in understanding hair structure occurred with the finding of transglutaminase activity in hair follicles (3, 4). The resulting extensive ⑀-(␥-glutamyl)lysine cross-linking accounted for the insolubility in the medulla of proteins, notably the major transglutaminase substrate, trichohyalin. A high content of isopeptide bonding has also been reported in the cuticle cells (5), rationalizing the low degree of protein extraction apparent ultramicroscopically even under harsh denaturing and reducing conditions (6).In recent years, identification of proteins participating in cross-linked structures in epidermis and appendages has benefited from the approach of peptide generation with enzymatic fragmentation followed by separation and amino acid sequencing of the peptides. Applied to the corneocyte-crosslinked envelope, a number of constituent proteins have been identified, including some where the isolated peptides were cross-linked, evidence of their participation in isopeptide bonds (7). Advances in current proteomic technology prompt application of this approach to the hair shaft where much of the protein resists extraction, and hence few data are available on the participants. It is evident, however, that much of the resistance is transglutaminase-dependent because hair from individuals afflicted by TGM1-negative lamellar ichthyosis is subject to considerable extraction (8). Present efforts using multidimensional protein identification technology (M...

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“…The crystalline phase consists of ␣-helical fraction of microfibrils with a low content of cysteine while the amorphous phase with a high content of cysteine contain non-helical fraction of microfibrils. Hard ␣-keratin fiber is a hierarchically structured material that shows a fibrous organization from the nanometer to the micrometer scale [3]. The matrix adheres to the filaments through secondary bonds including vander Waals's forces, hydrogen bonds and ionic interaction [2].…”

Section: Introductionmentioning

confidence: 99%