[Study of human leucine-rich amelogenin peptide and its regulation of mineralization by cryogenic transmission electron microscopy].
OBJECTIVE
Recombinant human leucine-rich amelogenin peptide (LRAP) was studied by cryogenic transmission electron microscopy (TEM); evaluation focused on its self-assembly and crystal growth in vitro.


METHODS
Human LRAP was recombined through prokaryotic expression vector pCold-SUMO and transformed into Escherichia coli BL21plys to acquire purified proteins. Cryogen TEM recorded assembly and self-assembling of LRAP from pH 3.5 to pH 8.0, and the hydroxyapatite crystal growth in the mixture of LRAP protein solution and artificial saliva was observed using TEM and selected area electron diffraction.


RESULTS
More than 90% purity LRAP was expressed, purified and identified as described in methods. LRAP linked into oligomers, nanospheres, nanochains, and microribbons, whereas pH value increased from 3.5 to 8.0. Mature hydroxyapatite crystal growth was guided in artificial saliva filled with calcium phosphate.


CONCLUSIONS
LRAP is simplified amelogenin functional domain and conserved the basic characters of amelogenin such as self-assembling and inducing crystallization along c axis. In the area of acellular synthesis of hydroxyapatite using extracellular enamel matrix protein, LRAP is one of candidate repair materials for irregular hard tissue defection. .
Dept. of Stomatology, Hospital of University of Electronic Science and Technology of China UESTC & Sichuan Provincial People's Hosptial, Chengdu 610072, China.
Tian
T
Kun
Dept. of Stomatology, Hospital of University of Electronic Science and Technology of China UESTC & Sichuan Provincial People's Hosptial, Chengdu 610072, China.
Feng
F
Xiaoyun
Dept. of Stomatology, Hospital of University of Electronic Science and Technology of China UESTC & Sichuan Provincial People's Hosptial, Chengdu 610072, China.
Du
D
Qin
Dept. of Stomatology, Hospital of University of Electronic Science and Technology of China UESTC & Sichuan Provincial People's Hosptial, Chengdu 610072, China.
Liao
L
Chuhang
Dept. of Stomatology, Hospital of University of Electronic Science and Technology of China UESTC & Sichuan Provincial People's Hosptial, Chengdu 610072, China.
Ren
R
Xiaohua
D053523:Amelogenin; D015519:Bone Density; D002130:Calcium Phosphates; D003460:Crystallization; D003743:Dental Enamel; D003746:Dental Enamel Proteins; D017886:Durapatite; D006801:Humans; D046529:Microscopy, Electron, Transmission
D053523:Amelogenin; D002130:Calcium Phosphates; D003746:Dental Enamel Proteins; C109069:enamel matrix proteins; C067432:leucine-rich amelogenin peptide; D017886:Durapatite; C020243:calcium phosphate
amelogenin; cryogenic transmission electron microscopy; hydroxyapatite; leucine-rich amelogenin peptide