Adsorption of Leucine-Rich Amelogenin Protein on Hydroxyapatite (001) Surface through −COO^- Claws

Abstract

Amelogenin is the main component of the organic matrix necessary to the formation of tooth enamel by directing the hydroxyapatite (HAP) growth. However, the detailed mechanism of adsorption between amelogenin and HAP is still not clear. In this report, simulations of the dynamic behavior of six different orientations of leucine-rich amelogenin protein (LRAP), the amelogenin splice variant, on a fixed hydrophilic HAP surface (001) were performed. Energy minimization, molecular dynamics (MD), and steered molecular dynamics (SMD) simulations were integrated in carrying this study. The results are highly consistent with the previous experimental findings. It was confirmed that the carboxyl groups contributed mainly to the adsorption of LRAP on the HAP (001) surface. Moreover, it was found that the −COO- claw of LRAP grasps the calcium ion with its two oxygen atoms in a special triangle form. This interaction form can resist external forces and is the key factor of the adsorption between LRAP and HAP.

Molecular dynamics simulations of the adsorption of amino acids on the hydroxyapatite {100}-water interface

“…Our simulation results indicate that charged and polar groups of amino acid (such as amino, carboxyl, hydroxyl group) could be firmly adsorbed on specific sites on the HAP crystal surface and multiple chelation could work together to enhance their interaction. Similar group interaction of amelogenin-like LRAP, BMPs proteins with HAP has also been found in our previous work by molecular simulation [15][16][17]. However, there were some differences between the simple AA and proteins.…”

“…Molecular dynamic (MD) simulation can provide useful information such as adsorption energy, adsorption and interaction sites and patterns of organic molecules on the HAP crystal faces since it can investigate the organic-inorganic interface at the atomic level [9][10][11][12][13][14][15][16][17]. Previously, we have employed MD simulation to investigate adsorption of glycine (Gly), glutamic acid (Glu) and proteins on HAP [13][14][15][16][17].…”

“…Previously, we have employed MD simulation to investigate adsorption of glycine (Gly), glutamic acid (Glu) and proteins on HAP [13][14][15][16][17]. In this study, the adsorptions of different type of amino acids (polar, aromatic, positive charged and negative charged) on the primary face of HAP, {100}, are investigated by MD simulation.…”

Kinetic study on the protein decomposition by photocatalytic Ti(IV)-doped calcium hydroxyapatite particles

“…7) Ca(NO 3 ) 2 and Ti(SO 4 ) 2 were dissolved in 1 dm 3 pure water free from CO 2 at an atomic ratio of Ti/(Ca+Ti) (abbreviated as X Ti ) was 0.2. The total amount of Ca and Ti in the solutions was hold at 0.1 mol; 0.060 mol of H 3 PO 4 was added to the solution and the solution pH was adjusted to 9.0 by adding a 15 M NH 4 OH solution. The resulting suspension was aged in a capped Teflon vessel of 100°C for 6 h. The particles generated were filtered off, thoroughly washed with 5 dm 3 deionized pure water, and finally dried at 70°C in an air oven for 24 h. To endow a high photocatalytic activity, TiHap particles with X Ti = 0.2 were further heat-treated with a temperature increment of 5°C/min until reaching 650°C and left during 1 h. Since these heat treated particles were stable and maintained high photocatalytic activity, 12) these particles were also preserved in a desiccator.…”

SYNTHESIS AND CHARACTERIZATION OF Mn-DOPED CALCIUM HYDROXYAPATITE PARTICLES

“…It is well known that a synthetic calcium hydroxyapatite Ca10(PO4)6(OH)2, designated as CaHap, attracts attention as bioceramics, acid-base catalysis in various reactions and adsorbents for separation of biomaterials [1][2][3][4][5][6] . Especially, CaHap bioceramics are one of basic materials used in bone implant surgery 7 .…”