Assembly of Amelogenin Proteolytic Products and Control of Octacalcium Phosphate Crystal Morphology

Abstract

The formation of enamel apatite crystals involves extracellular molecular events among which matrix assembly, interactions with growing crystals, and protein processing and removal are the subject of numerous investigations. Following the description of amelogenin nanospheres and the evidence for their presence in vivo as the principal structural component of developing dental enamel, we have focused our studies on investigating at the molecular level the process of nanosphere assembly and evaluating the effects of amelogenin on crystal growth and morphology. This paper is a short review of our recent studies with a focus on the assembly of amelogenin proteolytic products and their modulating effect on octacalcium phosphate (OCP) crystal morphology. In addition, we report that incorporation of amelogenins into 10% gelatin gel does not affect diffusion of calcium. This remarkable finding indicates that the observed modulation effect by amelogenin on OCP crystal morphology is not due to alteration of calcium diffusion into the gels but is the result of direct amelogenin-mineral interactions.

Roles of Electrostatics and Conformation in Protein-Crystal Interactions

“…Anionic proteins isolated from mineralized tissues have been shown to nucleate biomineral crystals [3], [4], [5], promote the formation of a particular polymorph [6], [7] or alter crystal growth habit [8], [9]. Protein-crystal interactions are also thought to prevent ectopic calcification [10].…”

Interface of synthetic inorganic biomaterials and bone regeneration

“…in the extracellular matrix (ECM) are in essence organized under the control of matrix proteins secreted by tissue-specific cells. ECMs which affects mineralization were collagen fibrils [40], osteocalcin [41], osteopontin [42,43], osteonectin [44], amelogenin [45], bone sialoprotein [42,46], and proteoglycan [36]. Another mineral-binding molecule with a role in the inhibition of mineralization is fetuin (alpha 2-HS glycoprotein), a circulating serum protein that accumulates in bone ECM [47].…”

Cellular uptake and processing of enamel matrix derivative by human periodontal ligament fibroblasts

“…The absence of any obvious gross aggregates at the cell membrane suggests that 20 kDa amelogenin was recognised at the cell membrane in its monomeric form or possibly as small homogeneous complexes similar to previously reported nanospheres. 14 Once internalised, the protein was concentrated in vesicle like structures, present in the cytoplasm. With time, internalized 20 kDa amelogenin appeared to be degraded, generating material at 5 kDa.…”