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Solid state NMR of salivary calculi: Proline-rich salivary proteins, citrate, polysaccharides, lipids, and organic–mineral interactions

Accepted version
Peer-reviewed

Repository DOI


Type

Article

Change log

Authors

Li, Y 
Reid, DG 
Bazin, D 
Daudon, M 
Duer, MJ 

Abstract

Solid state NMR (ssNMR) can characterize mineral (31P) and organic (13C) components of human salivary stones (n = 8). All show apatitic 31P spectra. 13C ssNMR indicates more protein, of more consistent composition, than apatitic uroliths, with signals from Tyr, Phe and His prominent. Citrate and lipid, identified by dipolar dephasing (DD), and polysaccharides are also observable in varying amounts. 13C{31P} rotational echo double resonance (13C{31P} REDOR) identifies carbon atoms in close (< ca. 0.5 nm) proximity to phosphorus and therefore probably binding with mineral. Citrate, sugar and carboxylate signals undergo strong 13C{31P} REDOR, also seen to signals between 50 and 60 ppm, from protein α- carbons and, possibly, phosphoserines and phospholipids, and sometimes to a 35 – 40 ppm envelope containing Asp-Cβ and Glu-Cγ signals. Amino acid analysis indicates high proline and aromatic content. 13C ssNMR and amino acid composition is consistent with preponderance of proline-rich salivary proteins such as statherin.

Description

Keywords

Apatite, Citrate, Polysaccharides, Proline-rich proteins, REDOR, Salivary proteins, Statherin

Journal Title

Comptes Rendus Chimie

Conference Name

Journal ISSN

1631-0748
1878-1543

Volume Title

Publisher

Cellule MathDoc/Centre Mersenne
Sponsorship
The U.K. EPSRC (Y. L.) and MRC (D. G. R.) for funding