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Akkineni S, Zhu C, Chen J, Song M, Hoff SE, Bonde J, Tao J, Heinz H, Habelitz S, De Yoreo JJ. Amyloid-like amelogenin nanoribbons template mineralization via a low-energy interface of ion binding sites. Proc Natl Acad Sci U S A 2022; 119:e2106965119. [PMID: 35522709 PMCID: PMC9172371 DOI: 10.1073/pnas.2106965119] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 03/16/2022] [Indexed: 12/02/2022] Open
Abstract
Protein scaffolds direct the organization of amorphous precursors that transform into mineralized tissues, but the templating mechanism remains elusive. Motivated by models for the biomineralization of tooth enamel, wherein amyloid-like amelogenin nanoribbons guide the mineralization of apatite filaments, we investigated the impact of nanoribbon structure, sequence, and chemistry on amorphous calcium phosphate (ACP) nucleation. Using full-length human amelogenin and peptide analogs with an amyloid-like domain, films of β-sheet nanoribbons were self-assembled on graphite and characterized by in situ atomic force microscopy and molecular dynamics simulations. All sequences substantially reduce nucleation barriers for ACP by creating low-energy interfaces, while phosphoserines along the length of the nanoribbons dramatically enhance kinetic factors associated with ion binding. Furthermore, the distribution of negatively charged residues along the nanoribbons presents a potential match to the Ca–Ca distances of the multi-ion complexes that constitute ACP. These findings show that amyloid-like amelogenin nanoribbons provide potent scaffolds for ACP mineralization by presenting energetically and stereochemically favorable templates of calcium phosphate ion binding and suggest enhanced surface wetting toward calcium phosphates in general.
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Affiliation(s)
- Susrut Akkineni
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195
- Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Cheng Zhu
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309
| | - Jiajun Chen
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195
- Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Miao Song
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195
- Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Samuel E. Hoff
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309
| | - Johan Bonde
- Division of Pure and Applied Biochemistry, Center for Applied Life Sciences, Lund University, Lund, SE-221 00, Sweden
| | - Jinhui Tao
- Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
| | - Hendrik Heinz
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO 80309
| | - Stefan Habelitz
- Department of Preventative and Restorative Dental Sciences, School of Dentistry, University of California, San Francisco, CA 94143
| | - James J. De Yoreo
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195
- Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352
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Bai Y, Bonde J, Carneiro KMM, Zhang Y, Li W, Habelitz S. A Brief History of the Discovery of Amelogenin Nanoribbons In Vitro and In Vivo. J Dent Res 2021; 100:1429-1433. [PMID: 34612757 DOI: 10.1177/00220345211043463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Without evidence for an organic framework, biological and biochemical processes observed during amelogenesis provided limited information on how extracellular matrix proteins control the development of the complex fibrous architecture of human enamel. Over a decade ago, amelogenin nanoribbons were first observed from recombinant proteins during in vitro mineralization experiments in our laboratory. In enamel from mice lacking the enzyme kallikrein 4 (KLK4), we later uncovered ribbon-like protein structures that matched the morphology, width, and thickness of the nanoribbons assembled by recombinant proteins. Interestingly, similar structures had already been described since the 1960s, when enamel sections from various mammals were demineralized and stained for transmission electron microscopy analysis. However, at that time, researchers were not aware of the ability of amelogenin to form nanoribbons and instead associated the filamentous nanostructures with possible imprints of mineral ribbons in the gel-like matrix of developing enamel. Further evidence for the significance of amelogenin nanoribbons for enamel development was stipulated when recent mineralization experiments succeeded in templating and orienting the growth of apatite ribbons along the protein nanoribbon framework. This article provides a brief historical review of the discovery of amelogenin nanoribbons in our laboratory in the context of reports by others on similar structures in the developing enamel matrix.
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Affiliation(s)
- Y Bai
- Department of Preventative and Restorative Dental Sciences, School of Dentistry, University of California, San Francisco, CA, USA
| | - J Bonde
- Division of Pure and Applied Biochemistry, Center of Applied Life Science, Lund University, Lund, Sweden
| | - K M M Carneiro
- Faculty of Dentistry, University of Toronto, Toronto, Canada
| | - Y Zhang
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, CA, USA
| | - W Li
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of California, San Francisco, CA, USA
| | - S Habelitz
- Department of Preventative and Restorative Dental Sciences, School of Dentistry, University of California, San Francisco, CA, USA
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