Ameloblastin (AMBN) is a protein expressed mainly during dental hard tissue development. Biochemically, it is classified as an intrinsically disordered protein (IDP). Its biological role remains largely unknown; however, the question of AMBN function will undoubtedly be connected to its structural properties and its potential for protein-protein and protein-cell interactions. A basic biophysical characterization of human recombinant ameloblastin (hrAMBN) and its N- and C-terminal domains by means of circular dichroism spectroscopy and dynamic light scattering showed that under physiological conditions ameloblastin is an IDP with a prevalent polyproline-II (PPII) conformation. Both the N- and C-terminal polypeptides, when expressed independently, showed different structural preferences upon heating as well as different behaviour in the presence of trifluoroethanol and CaCl(2) salt. The N-terminal peptide showed a more ordered structure with a strong tendency to adopt a helical conformation upon the addition of trifluorethanol, whereas the C-terminal domain seemed to be primarily responsible for the structural disorder of the entire AMBN molecule.

Institute of Microbiology v v i Academy of Sciences of Czech Republic Vídeňská 1083 142 20 Prague 4 Czech Republic

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Oligomerization Function of the Native Exon 5 Sequence of Ameloblastin Fused with Calmodulin

Proteolytic profiles of two isoforms of human AMBN expressed in E. coli by MMP-20 and KLK-4 proteases

Xeno-Hybrid Bone Graft Releasing Biomimetic Proteins Promotes Osteogenic Differentiation of hMSCs

Characterization of AMBN I and II Isoforms and Study of Their Ca2+-Binding Properties

Phosphorylation Modulates Ameloblastin Self-assembly and Ca 2+ Binding

Intrinsically disordered proteins drive enamel formation via an evolutionarily conserved self-assembly motif

Intrinsically disordered enamel matrix protein ameloblastin forms ribbon-like supramolecular structures via an N-terminal segment encoded by exon 5