Progression of Self-Assembly of Amelogenin Protein Supramolecular Structures in Simulated Enamel Fluid.

ABSTRACT: Mechanisms of protein-guided mineralization in enamel, leading to organized fibrillar apatite nanocrystals, remain elusive. In vitro studies reveal recombinant human amelogenin (rH174), a matrix protein templating this process, self-assembles into a variety of structures. This study endeavors to clarify the self-assembly of rH174 in physiologically relevant conditions. Self-assembly in simulated enamel fluid was monitored up to 2 months. At alkali (7.3-8.7) and acidic (5.5-6.1) pH ranges, a distinct progression in formation was observed from nanospheres (17-23 nm) to intermediate-length nanorods, concluding with the formation of long 17-18 nm wide nanoribbons decorated with nanospheres. Assembly in acidic condition progressed quicker to nanoribbons with fewer persistent nanospheres. X-ray diffraction exhibited reflections characteristic of antiparallel ?-sheets (4.7 and 9.65 Å), supporting the model of amyloid-like nanoribbon formation. This is the first observation of rH174 nanoribbons at alkaline pH as well as concurrent nanosphere formation, indicating both supramolecular structures are stable together under physiological conditions.

SUBMITTER: Engelberth SA 

PROVIDER: S-EPMC6648677 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature