Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

The leucine-rich amelogenin protein (LRAP) is primarily monomeric and unstructured in physiological solution

Journal Article · · Journal of Structural Biology
 [1];  [2];  [2];  [3];  [1];  [4];  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Alliance Protein Lab., Inc., San Diego, CA (United States)
  3. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  4. WSP Chemicals & Technology, LLC, Leetsdale, PA (United States)

Amelogenin proteins are critical to the formation of enamel in teeth and may have roles in promoting nucleation, controlling growth, and regulating microstructures of the intricately woven hydroxyapatite (HAP). Leucine-rich amelogenin protein (LRAP) is a 59-residue splice variant of amelogenin and contains the N- and C-terminal charged regions of the full-length protein thought to control crystal growth. Although the quaternary structure of full-length amelogenin in solution has been well studied and can consist of self-assemblies of monomers called nanospheres, the quaternary structure of LRAP is not as well studied. Here, analytical ultracentrifugation sedimentation velocity (SV) and small angle neutron scattering (SANS) were used to study the tertiary and quaternary structure of LRAP over a range of pH values, ionic strengths, and concentrations. SV has advantages over other techniques in accurately quantifying protein speciation in polydisperse solutions. We found that the monomer was the dominant species of phosphorylated LRAP (LRAP(+P)) over a range of solution conditions (pH 2.7 to 4.1, pH 4.5 to 8, 50 mmol/L( mM) to 200 mM NaCl, 0.065 to 2 mg/mL). The monomer was also the dominant species for unphosphorylated LRAP (LRAP(-P)) at pH 7.4 and LRAP(+P) in the presence of 2.5 mM calcium at pH 7.4. LRAP aggregated in a narrow pH range near the isoelectric point (pH 4.1). We conclude that LRAP does not form nanospheres under physiological solution conditions. Both SV and SANS showed that the LRAP monomer has a radius of ~2.0 nm and adopts an extended structure which solution NMR studies show is intrinsically disordered. This work provides new insights into the tertiary and quaternary structure of LRAP and further evidence that the monomeric species is an important functional form of amelogenins

Research Organization:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Grant/Contract Number:
AC05-76RL01830
OSTI ID:
1182923
Alternate ID(s):
OSTI ID: 1359491
Report Number(s):
PNNL-SA--105350; 44691; 41891; 48235; 47735; 400412000
Journal Information:
Journal of Structural Biology, Journal Name: Journal of Structural Biology Journal Issue: 1 Vol. 190; ISSN 1047-8477
Publisher:
ElseiverCopyright Statement
Country of Publication:
United States
Language:
English

References (63)

Interaction of amelogenin with hydroxyapatite crystals: An adherence effect through amelogenin molecular self-association journal October 1998
Detection of monodisperse aggregates of a recombinant amelogenin by dynamic light scattering journal October 1994
Scalable molecular dynamics with NAMD journal January 2005
Flexible Structures of SIBLING Proteins, Bone Sialoprotein, and Osteopontin journal January 2001
Evidence for Amelogenin "Nanospheres" as Functional Components of Secretory-Stage Enamel Matrix journal July 1995
Temperature and pH-Dependent Supramolecular Self-Assembly of Amelogenin Molecules: A Dynamic Light-Scattering Analysis journal January 1998
The Structural Biology of the Developing Dental Enamel Matrix journal June 1999
Self-Assembly Properties of Recombinant Engineered Amelogenin Proteins Analyzed by Dynamic Light Scattering and Atomic Force Microscopy journal July 2000
1H, 13C and 15N chemical shift referencing in biomolecular NMR journal September 1995
Critical Evaluation of Nanoparticle Tracking Analysis (NTA) by NanoSight for the Measurement of Nanoparticles and Protein Aggregates journal March 2010
Cyclical changes in pH in bovine developing enamel as sequential bands journal January 1991
Identification of the leucine-rich amelogenin peptide (LRAP) as the translation product of an alternatively spliced transcript journal February 1991
Size-Distribution Analysis of Macromolecules by Sedimentation Velocity Ultracentrifugation and Lamm Equation Modeling journal March 2000
Properties of dissociatively extracted fetal tooth matrix proteins. I. Principal molecular species in developing bovine enamel. journal October 1980
Amelogenins: assembly, processing and control of crystal morphology journal September 2001
The Amelogenin Proteins and Enamel Development in Humans and Mice journal January 2011
Improved methods for fitting sedimentation coefficient distributions derived by time-derivative techniques journal July 2006
Enamel formation in vitro in mouse molar explants exposed to amelogenin polypeptides journal December 2007
A solution NMR investigation into the murine amelogenin splice-variant LRAP (Leucine-Rich Amelogenin Protein) journal September 2010
Leucine-rich amelogenin peptide induces osteogenesis in mouse embryonic stem cells journal February 2008
Leucine-rich amelogenin peptide induces osteogenesis by activation of the Wnt pathway journal September 2009
The influence of Leucine-rich amelogenin peptide on MSC fate by inducing Wnt10b expression journal September 2011
Bone sialoprotein expression enhances osteoblast differentiation and matrix mineralization in vitro journal September 2007
SASSIE: A program to study intrinsically disordered biological molecules and macromolecular ensembles using experimental scattering restraints journal February 2012
The nucleation and growth of calcium phosphate by amelogenin journal June 2007
The leucine rich amelogenin protein (LRAP) adsorbs as monomers or dimers onto surfaces journal March 2010
Leucine rich amelogenin peptide alters ameloblast differentiation in vivo journal October 2013
Comparison of the crystal and solution structures of calmodulin and troponin C journal February 1988
Phosphorylation and Ionic Strength Alter the LRAP–HAP Interface in the N-Terminus journal March 2013
A Solution NMR Investigation into the Early Events of Amelogenin Nanosphere Self-Assembly Initiated with Sodium Chloride or Calcium Chloride journal November 2008
The Tooth Enamel Protein, Porcine Amelogenin, Is an Intrinsically Disordered Protein with an Extended Molecular Configuration in the Monomeric Form journal March 2009
Phosphorylated Proteins and Control over Apatite Nucleation, Crystal Growth, and Inhibition journal October 2008
Adsorption of Leucine-Rich Amelogenin Protein on Hydroxyapatite (001) Surface through −COO - Claws journal December 2006
Partial High-Resolution Structure of Phosphorylated and Non-phosphorylated Leucine-Rich Amelogenin Protein Adsorbed to Hydroxyapatite journal June 2011
Neutron Reflectometry Studies of the Adsorbed Structure of the Amelogenin, LRAP journal March 2013
All-Atom Empirical Potential for Molecular Modeling and Dynamics Studies of Proteins journal April 1998
Control of octacalcium phosphate and apatite crystal growth by amelogenin matrices journal January 2004
Activation of recombinant bovine matrix metalloproteinase-20 and its hydrolysis of two amelogenin oligopeptides: Activation of recombinant bovine matrix metalloproteinase-20 and its hydrolysis of two amelogenin oligopeptides journal October 1999
Hierarchical self-assembly of amelogenin and the regulation of biomineralization at the nanoscale journal August 2011
Determination of the Conformations of cAMP Receptor Protein and Its T127L,S128A Mutant with and without cAMP from Small Angle Neutron Scattering Measurements journal August 1998
The COOH Terminus of the Amelogenin, LRAP, Is Oriented Next to the Hydroxyapatite Surface journal August 2004
Specific Amelogenin Gene Splice Products Have Signaling Effects on Cells in Culture and in Implants in Vivo journal December 2000
Amelogenin-deficient Mice Display an Amelogenesis Imperfecta Phenotype journal June 2001
Dissecting Amelogenin Protein Nanospheres: CHARACTERIZATION OF METASTABLE OLIGOMERS journal August 2011
Differential Effect of Amelogenin Peptides on Osteogenic Differentiation In Vitro : Identification of Possible New Drugs for Bone Repair and Regeneration journal June 2012
Reduction and analysis of SANS and USANS data using IGOR Pro journal November 2006
GNOM – a program package for small-angle scattering data processing journal October 1991
The 30 m Small-Angle Neutron Scattering Instruments at the National Institute of Standards and Technology journal June 1998
Modern analytical ultracentrifugation in protein science: A tutorial review journal September 2002
Enamel matrix derivative (EMDOGAINR) in the treatment of intrabony periodontal defects journal September 1997
Ten-year results following treatment of intra-bony defects with enamel matrix proteins and guided tissue regeneration journal September 2008
Self-assembly and effect on crystal growth of the leucine-rich amelogenin peptide journal May 2006
Comparative calcium binding of leucine-rich amelogenin peptide and full-length amelogenin journal May 2006
Rescue of the murine amelogenin null phenotype with two amelogenin transgenes: Amelogenin null rescue journal December 2011
The Leucine-Rich Amelogenin Peptide Alters the Amelogenin Null Enamel Phenotype journal August 2008
Mmp-20 and Klk4 Cleavage Site Preferences for Amelogenin Sequences journal September 2009
Leucine-rich Amelogenin Peptides Regulate Mineralization in vitro journal May 2011
Quantitative Analysis of Amelogenin Solubility journal June 1998
Bone Sialoprotein journal January 1999
The Effect of LRAP on Enamel Organ Epithelial Cell Differentiation journal November 2007
Protein Interactions During Assembly of the Enamel Organic Extracellular Matrix journal February 1997
Leucine-Rich Amelogenin Peptide: A Candidate Signaling Molecule During Cementogenesis journal August 2004
Analysis of Amelogenin Proteins Using Monospecific Antibodies to Defined Sequences journal January 1995

Cited By (3)


Similar Records

Neutron Reflectometry Studies of the Adsorbed Structure of the Amelogenin, LRAP
Journal Article · Thu Mar 21 00:00:00 EDT 2013 · Journal of Physical Chemistry B, 117(11):3098-3109 · OSTI ID:1082600

The leucine rich amelogenin protein (LRAP) adsorbs as monomers or dimers onto surfaces
Journal Article · Mon Mar 15 00:00:00 EDT 2010 · Journal of Structural Biology, 169(3):266-276 · OSTI ID:974941

A Solution NMR Investigation into the Murine Amelogenin Splice-Variant LRAP (Leucine-Rich Amelogenin Protein).
Journal Article · Wed Sep 01 00:00:00 EDT 2010 · Biochimica et Biophysica Acta--Proteins and Proteomics, 1804(9):1768-1774 · OSTI ID:988613