HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (13) Citing Articles via Google Scholar Google Scholar Articles by Margolis, H.C. Articles by Fowler, C.E. Search for Related Content PubMed PubMed Citation Articles by Margolis, H.C. Articles by Fowler, C.E.

Role of Macromolecular Assembly of Enamel Matrix Proteins in Enamel Formation

¹ Department of Biomineralization, The Forsyth Institute, 140 The Fenway, Boston, MA 02115, USA; and
² GlaxoSmithKline, Weybridge, Surrey, UK

View larger version (195K): [in a new window]   Figure 1. Parallel arrays of enamel crystals (monkey) and in cross-section within orthogonal enamel rods (courtesy of Dr. Ziedonis Skobe).

View larger version (44K): [in a new window]   Figure 2. Aligned amino acid sequences of porcine, murine, and bovine amelogenins. Red amino acids are identical in all three sequences. N-terminal methionine (bold, underscored) is missing in noted recombinant proteins. Serine-16 (bold, underscored) is phosphorylated in the native proteins, although it is lacking in the recombinant amelogenins.

View larger version (15K): [in a new window]   Figure 3. Solubility of recombinant and native amelogenins. (a) Solubility of rM179 and rM166 in 0.05 M potassium phosphate buffer, 0.15 M ionic strength, 25°C, as a function of pH. (b) Solubility of the 25K, 23K, and 20K porcine amelogenins under the same conditions. (Reprinted from Tan et al., 1998, with permission.) The 25K, 23K, and 20K proteins are analogous to P173, P161, and P148, respectively.

View larger version (21K): [in a new window]   Figure 4. Radii Rs and Rh (A), numbers of protein molecules N per particle (B), and apparent protein densities d of particles of rM179 (C), as measured by means of small-angle x-ray scattering (SAXS) and dynamic light scattering (DLS) during heating and subsequent cooling of the protein solution (2 mg/mL, pH 8). Heating the sample led to an irreversible increase of the hydrodynamic radius and number of protein molecules per particle, along with a decrease of the apparent density evaluated from DLS data. In contrast, the corresponding parameters measured by means of SAXS showed only a comparatively weak effect. (Reprinted from Aichmayer et al., 2005, with permission from Elsevier.)

View larger version (31K): [in a new window]   Figure 5. Proposed model for the onset of nanosphere aggregation at pH 8. At low temperatures (room temperature and below), amelogenin assembles into nanospheres with a dense (hydrophobic) core surrounded by a shell of (hydrophilic and negatively charged) chain segments. The SAXS radius Rs is related to the core, whereas the hydrodynamic radius Rh is related to the overall size of the particle. At higher temperatures, the repulsion between spheres is reduced (possibly due to a collapse of the chains onto the core) and agglomeration of the nanospheres starts. (Reprinted from Aichmayer et al., 2005, with permission from Elsevier.)

View larger version (62K): [in a new window]   Figure 6. TEM micrographs of crystalline aggregates formed in the presence of monomeric rM179 (A), monomeric rM166 (B), and pre-assembled rM179 (C), and their corresponding electron diffraction patterns (inserts). (Reprinted [with modification] from Beniash et al., 2005, with permission from Elsevier.)

View larger version (40K): [in a new window]   Figure 7. Proposed model for the formation of BaSO4 nanofilament bundles through time-dependent transformations of surfactant-coated amorphous inorganic nanoparticles. (Reprinted with permission from Li and Mann, 2000. Copyright [2000] American Chemical Society.)

View larger version (175K): [in a new window]   Figure 8. Bundles of aligned filaments of hydroxyapatite prepared with high concentrations of AOT [sodium bis-(2-ethylhexylsulfosuccinate)] and a low concentration of water, with a small quantity of m-xylene co-solvent. Insert: Electron diffraction pattern of the bundles showing (arrow) an arc pattern, confirming the alignment of the hydroxyapatite filaments. (Reprinted from Fowler et al., 2005, with permission from The Royal Society of Chemistry.)