Amyloid structure of high-order assembly of Leucine-rich amelogenin revealed by solid-state NMR

• Published in: Journal of structural biology Vol. 206; no. 1; pp. 29 - 35
• Main Authors: Ma, Cheng-Wei, Zhang, Jing, Dong, Xing-Qi, Lu, Jun-Xia
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2019
• Subjects: Amyloid structure; Enamel biomineralization; Matrix protein; Secondary structure; Self-assembly; Solid-state NMR; THT; Solid-state NMR; TEV; DSS; AFM; DLS; XRD; SSNMR; Secondary structure; Amyloid structure; Self-assembly; LRAP; Enamel biomineralization; Matrix protein; TEM; MAS
• ISSN: 1047-8477; 1095-8657
• DOI: 10.1016/j.jsb.2018.03.009

High-order assemblies of amelogenin, the major protein in enamel protein matrix, are believed to act as the template for enamel mineral formation. The Leucine-rich amelogenin (LRAP) is a natural splice-variant of amelogenin, a functional protein in vivo, containing conserved domains of amelogenin. In this work, we showed LRAP aggregates hierarchically into assemblies with various sizes including scattered beads, beads-on-a-string and gel-like precipitations in the presence of both calcium and phosphate ions. Solid-state NMR combined with X-ray diffraction and microscopic techniques, was applied to give a picture of LRAP self-assemblies at the atomic level. Our results, for the first time, confirmed LRAP assemblies with different sizes all contained a consistent rigid segment with β-sheet secondary structure (residues 12–27) and the β-sheet segment would further assemble into amyloid-like structures.