The 32kDa enamelin undergoes conformational transitions upon calcium binding
Daming Fan1, Rajamani Lakshminarayanan, Janet Moradian-Oldak
1University of Southern California, School of Dentistry, Center for Craniofacial Molecular Biology, 2250 Alcazar Street CSA 103, Los Angeles, CA 90033, USA.
Journal of Structural Biology
|May 30, 2008
Summary
Enamelin, a key protein in tooth enamel formation, changes structure in response to calcium ions. This conformational shift may facilitate enamelin
Area of Science:
- Biochemistry
- Biomineralization
- Structural Biology
Background:
- Enamelin is a crucial glycoprotein fragment involved in enamel biomineralization.
- Its role in controlling crystal nucleation and growth is vital for enamel formation.
Purpose of the Study:
- To investigate the structural changes of 32 kDa enamelin in response to calcium ions.
- To elucidate the mechanism of enamelin-mineral interaction during biomineralization.
Main Methods:
- Circular dichroism (CD) spectroscopy
- Fourier transform infrared (FTIR) spectroscopy
- Quantitative analysis of CD data
Main Results:
- 32 kDa enamelin exhibits a high alpha-helix content (81.5%) in its secondary structure.
- Calcium ions induce a conformational change towards a beta-sheet preference in enamelin.
- A low calcium association constant (K(a)=1.55 x 10(3)M(-1)) was determined for 32 kDa enamelin.
Conclusions:
- The calcium-induced beta-sheet conformation may enhance enamelin's interaction with apatite crystal surfaces.
- These findings offer new insights into enamelin's function in enamel biomineralization.
- Understanding enamelin-mineral interactions is key to comprehending enamel formation.
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