The leucine rich amelogenin protein (LRAP) adsorbs as monomers or dimers onto surfaces
Amelogenin and amelogenin splice variants are believed to be involved in controlling the formation of the highly anisotropic and ordered hydroxyapatite crystallites that form enamel. The adsorption behavior of amelogenin proteins onto substrates is very important because protein-surface interactions are critical to it’s function. We have studied the adsorption of LRAP, a splice variant of amelogenin which may also contribute to enamel function, onto model self-assembled monolayers on gold containing of COOH, CH3, and NH2 end groups. Dynamic light scattering (DLS) experiments indicated that LRAP in phosphate buffered saline (PBS) and solutions at saturation with calcium phosphate contained aggregates of nanospheres. Null ellipsometry and atomic force microscopy (AFM) were used to study protein adsorption amounts and structures. Relatively high amounts of adsorption occurred onto the CH3 and NH2 surfaces from both calcium phosphate and PBS solutions. Adsorption was also promoted onto COOH surfaces when calcium was present in the solutions suggesting an interaction that involves calcium bridging with the negatively charged C-terminus. The ellipsometry and AFM studies suggested that the protein adsorbed onto all surfaces as LRAP monomers. We propose that the monomers adsorb onto the surfaces by disassembling or “shedding” from the nanospheres that are present in solution. This work reveals the importance of small subnanosphere-sized structures of LRAP at interfaces, structures that may be important in the biomineralization of tooth enamel.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 974941
- Report Number(s):
- PNNL-SA-62449; JSBIEM; 8993; 19851a; 19851; 2466; 17092; 1724; 453040220
- Journal Information:
- Journal of Structural Biology, 169(3):266-276, Vol. 169, Issue 3; ISSN 1047-8477
- Country of Publication:
- United States
- Language:
- English
Similar Records
The leucine-rich amelogenin protein (LRAP) is primarily monomeric and unstructured in physiological solution
Adsorption of Amelogenin onto Self-Assembled and Fluoroapatite Surfaces