Characterization of inter-crystallite peptides in human enamel rods reveals contribution by the Y allele of amelogenin
| Autor: | Michael V. Swain, Peter G. Hains, Neil Hunter, Catherine Rathsam, Nattida Charadram, Hans Zoellner, Ramin Mostofi Zadeh Farahani, Valentina A. Valova |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Peptide Mass Spectrometry 03 medical and health sciences Exon 0302 clinical medicine Dental Enamel Proteins stomatognathic system Structural Biology Humans AMBN Dental Enamel Alleles chemistry.chemical_classification Amelogenin Enamel paint Exons 030206 dentistry Immunogold labelling Molecular biology Fetuin Enamel rod stomatognathic diseases 030104 developmental biology chemistry visual_art Microscopy Electron Scanning visual_art.visual_art_medium Keratins Electrophoresis Polyacrylamide Gel |
| Zdroj: | Journal of Structural Biology. 204:26-37 |
| ISSN: | 1047-8477 |
| Popis: | Proteins of the inter-rod sheath and peptides within the narrow inter-crystallite space of the rod structure are considered largely responsible for visco-elastic and visco-plastic properties of enamel. The present study was designed to investigate putative peptides of the inter-crystallite space. Entities of 1–6 kDa extracted from enamel rods of erupted permanent teeth were analysed by mass spectrometry (MS) and shown to comprise N-terminal amelogenin (AMEL) peptides either containing or not containing exon 4 product. Other dominant entities consisted of an N-terminal peptide from ameloblastin (AMBN) and a series of the most hydrophobic peptides from serum albumin (ALBN). Amelogenin peptides encoded by the Y-chromosome allele were strongly detected in Enamel from male teeth. Location of N-terminal AMEL peptides as well as AMBN and ALBN, between apatite crystallites, was disclosed by immunogold scanning electron microscopy (SEM). Density plots confirmed the relative abundance of these products including exon 4+ AMEL peptides that have greater capacity for binding to hydroxyapatite. Hydrophilic X and Y peptides encoded in exon 4 differ only in substitution of non-polar isoleucine in Y for polar threonine in X with reduced disruption of the hydrophobic N-terminal structure in the Y form. Despite similarity of X and Y alleles of AMEL the non-coding region upstream from exon 4 shows significant variation with implications for segregation of processing of transcripts from exon 4. Detection of fragments from multiple additional proteins including keratins (KER), fetuin A (FETUA), proteinases and proteinase inhibitors, likely reflect biochemical events during enamel formation. |
| Databáze: | OpenAIRE |
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