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Effect of phosphorylation on the interaction of calcium with leucine‐rich amelogenin peptide
Author(s) -
Le Norcy Elvire,
Kwak SeoYoung,
Allaire Marc,
Fratzl Peter,
Yamakoshi Yasuo,
Simmer James P.,
Margolis Henry C.
Publication year - 2011
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.2011.00900.x
Subject(s) - chemistry , amelogenin , peptide , calcium , crystallography , phosphorylation , biophysics , biochemistry , gene , organic chemistry , biology
Le Norcy E, Kwak S‐Y, Allaire M, Fratzl P, Yamakoshi Y, Simmer JP, Margolis HC. Effect of phosphorylation on the interaction of calcium with leucine‐rich amelogenin peptide.
Eur J Oral Sci 2011; 119 (Suppl. 1): 97–102. © 2011 Eur J Oral Sci Amelogenin undergoes self‐assembly and plays an essential role in guiding enamel mineral formation. The leucine‐rich amelogenin peptide (LRAP) is an alternative splice product of the amelogenin gene and is composed of the N terminus (containing the only phosphate group) and the C terminus of full‐length amelogenin. This study was conducted to investigate further the role of phosphorylation in LRAP self‐assembly in the presence and absence of calcium using small angle X‐ray scattering (SAXS). Consistent with our previous dynamic light‐scattering findings for phosphorylated (+P) and non‐phosphorylated (−P) LRAP, SAXS analyses revealed radii of gyration ( R g ) for LRAP(−P) (46.3–48.0 Å) that were larger than those for LRAP(+P) (25.0–27.4 Å) at pH 7.4. However, added calcium (up to 2.5 mM) induced significant increases in the R g of LRAP(+P) (up to 46.4 Å), while it had relatively little effect on LRAP(−P) particle size. Furthermore, SAXS analyses suggested compact folded structures for LRAP(−P) in the presence and absence of calcium, whereas the conformation of LRAP(+P) changed from an unfolded structure to a more compact structure upon the addition of calcium. We conclude that the single phosphate group in LRAP(+P) induces functionally important conformational changes, suggesting that phosphorylation may also influence amelogenin conformation and protein–mineral interactions during the early stages of amelogenesis.