Interaction of calcium ions and salivary acidic proline-rich proteins with hydroxyapatite. A possible aspect of inhibition of hydroxyapatite formation.
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ABSTRACT:
SUBMITTER: Bennick A
PROVIDER: S-EPMC1152083 | biostudies-other | 1983 Jul
REPOSITORIES: biostudies-other
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Project description:Protein A and C, which are major components of the acidic proline-rich proteins in human saliva, were digested, before or after adsorption to hydroxyapatite, with alkaline phosphatase, trypsin, thermolysin and a proteinase preparation from salivary sediment. The results demonstrate that the binding site is located in the proline-poor N-terminal part of the protein, possibly between residues 3 and 25. Phosphoserine is necessary for maximal adsorption of the proteins to hydroxyapatite. When proteins A and C are adsorbed to hydroxyapatite before proteolytic digestion there is a protection of some of the susceptible bonds in the N-terminal part of the proteins and a gradual removal of the proline-rich C-terminal part. Thermolysin can cleave susceptible bonds in the part of the protein that remains bound to hydroxyapatite, but at least some of the resulting peptides are retained on the mineral. Since the ability of the proteins to inhibit hydroxyapatite formation and to bind calcium is located in the N-terminal proline-poor part, it is possible that these activities are retained after proteolytic digestion of the adsorbed proteins.
| S-EPMC1161479 | biostudies-other
Project description:Human saliva contains a large number of phosphopeptides derived by cleavage of acidic proline-rich proteins (APRPs). These peptides were purified by column chromatography and they constituted 0.5% of APRPs in parotid saliva, but 11% of APRPs in saliva expectorated from the mouth (whole saliva), indicating that there is considerable cleavage of APRPs after secretion from the gland. Similarly to APRP, the phosphopeptides bind Ca2+, but they accounted for only 4% of protein-bound Ca2+ in whole saliva. APRPs as well as the phosphopeptides inhibited formation of hydroxyapatite, but, whereas 19-20 micrograms of APRP was needed for 50% inhibition, only 0.7-3.3 micrograms of purified peptides was needed for the same degree of activity, and the phosphopeptides accounted for 18% of total inhibitory activity in whole saliva. All phosphopeptides adsorbed on hydroxyapatite in vitro, and adsorption of phosphopeptides on tooth surfaces in vivo could also be demonstrated, indicating that they would be able to inhibit unwanted mineral formation on the tooth surface in vivo. Degradation of APRPs after secretion therefore does not lead to a loss of their biological activities.
| S-EPMC1131719 | biostudies-other
Project description:Three basic proline-rich salivary proteins have been produced through the recombinant route. IB5 is a small basic proline-rich protein that is involved in the binding of plant tannins in the oral cavity. II-1 is a larger protein with a closely related backbone; it is glycosylated, and it is also able to bind plant tannins. II-1 ng has the same polypeptidic backbone as II-1, but it is not glycosylated. Small angle x-ray scattering experiments on dilute solutions of these proteins confirm that they are intrinsically disordered. IB5 and II-1 ng can be described through a chain model including a persistence length and cross section. The measured radii of gyration (Rg=27.9 and 41.0+/-1 A respectively) and largest distances (rmax=110 and 155+/-10 A respectively) show that their average conformations are rather extended. The length of the statistical segment (twice the persistence length) is b=30 A, which is larger than the usual value (18 A-20 A) for unstructured polypeptide chains. These characteristics are presumably related to the presence of polyproline helices within the polypeptidic backbones. For both proteins, the radius of gyration of the chain cross-section is Rc=2.7+/-0.2A. The glycosylated protein II-1 has similar conformations but the presence of large polyoside sidegroups yields the structure of a branched macromolecule with the same hydrophobic backbone and hydrophilic branches. It is proposed that the unusually extended conformations of these proteins in solution facilitate the capture of plant tannins in the oral cavity.
| S-EPMC2905104 | biostudies-literature
Project description:Early childhood caries affects 28% of children aged 2-6 in the US and is not decreasing. There is a well-recognized need to identify susceptible children at birth. Caries-free adults neutralize bacterial acids in dental biofilms better than adults with severe caries. Saliva contains acidic and basic proline-rich proteins (PRPs) which attach to oral streptococci. The PRPs are encoded within a small region of chromosome 12. An acidic PRP allele (Db) protects Caucasian children from caries but is more common in African Americans. Some basic PRP allelic phenotypes have a three-fold greater frequency in caries-free adults than in those with severe caries. Early childhood caries may associate with an absence of certain basic PRP alleles which bind oral streptococci, neutralize biofilm acids, and are in linkage disequilibrium with Db in Caucasians. The encoding of basic PRP alleles is updated and a new technology for genotyping them is described.
| S-EPMC3235478 | biostudies-literature
Project description:Human basic proline-rich proteins and basic glycosylated proline-rich proteins are the most complex family of human adult salivary proteins, secreted only by the parotid gland, expressed by the polymorphic PRB1-4 genes. This study reports the results obtained for their characterization in our laboratory utilizing integrated top-down and bottom-up HPLC-ESI-MS and MS/MS platform. The family include 11 parent peptides/proteins and more than 6 parent glycosylated proteins. Despite the complexity, on the basis of their primary structure they result the product of the duplication of three repeats and we propose that they can be classified in two main groups, the first including the peptides called P-E, P-Ko, IB-6, Ps-1, Ps-2, P-H, P-F, P-J, and P-D, the second including the peptides called IB-1, II-2 and the glycosylated basic proline-rich proteins codified by PRB3 and PRB4 genes. A third minor hybrid group includes the proteins called IB-8a Con1- and Con1+. Some of the proteins of the family (IB-1, II-2 and P-J) are almost always detectable in adult human saliva, while the others are expressed with different frequencies according to the phenotype. Various isoforms are detectable in the adult saliva and three of them, until now not reported (P-H S1→A, P-Ko P36→S, P-Ko A41→S), were characterized by MS/MS fragmentation.
2018-08-08 | PXD009813 | Pride
Project description:Actinomyces spp. exhibit type 1 fimbria-mediated adhesion to salivary acidic proline-rich proteins (PRPs) and statherin ligands. Actinomyces spp. with different animal and tissue origins belong to three major adhesion types as relates to ligand specificity and type 1 fimbria genes. (i) In preferential acidic-PRP binding, strains of Actinomyces naeslundii genospecies 1 and 2 from human and monkey mouths displayed at least three ligand specificities characterized by preferential acidic-PRP binding. Slot blot DNA hybridization showed seven highly conserved type 1 fimbria genes (orf1- to -6 and fimP) in genospecies 1 and 2 strains, except that orf5 and orf3 were divergent in genospecies 1. (ii) In preferential statherin binding, oral Actinomyces viscosus strains of rat and hamster origin (and strain 19246 from a human case of actinomycosis) bound statherin preferentially. DNA hybridization and characterization of the type 1 fimbria genes from strain 19246 revealed a homologous gene cluster of four open reading frames (orfA to -C and fimP). Bioinformatics suggested sortase (orfB, orf4, and part of orf5), prepilin peptidase (orfC and orf6), fimbria subunit (fimP), and usher- and autotransporter-like (orfA and orf1 to -3) functions. Those gene regions corresponding to orf3 and orf5 were divergent, those corresponding to orf2, orf1, and fimP were moderately conserved, and those corresponding to orf4 and orf6 were highly conserved. Restriction fragment length polymorphism analyses using a fimP probe separated human and monkey and rat and hamster strains into phylogenetically different groups. (iii) In statherin-specific binding, strains of A. naeslundii genospecies 1 from septic and other human infections displayed a low-avidity binding to statherin. Only the orf4 and orf6 gene regions were highly conserved. Finally, rat saliva devoid of statherin bound bacterial strains avidly irrespective of ligand specificity, and specific antisera detected either type 1, type 2, or both types of fimbria on the investigated Actinomyces strains.
| S-EPMC98805 | biostudies-literature
Project description:Human glandular salivary secretions contain several acidic proline-rich phosphoproteins (PRPs). These proteins have important biological functions related to providing a protective environment for the teeth, and appear to possess other activities associated with modulation of adhesion of bacteria to oral surfaces. These functions and activities depend on the primary structures of the PRPs. Previously determined amino acid sequences of two 150-residue molecules, PRP-1 and PRP-2, and two related 106-residue proteins, PRP-3 and PRP-4, indicated that residue 4 was Asn in PRP-1 and PRP-3, and Asp in PRP-2 and PRP-4, and position 50 was Asn in all four proteins. Recent data from cDNA sequence studies and further structural studies, however, showed that the previously proposed sequences cannot be completely correct. The present work has shown that the protein previously designated as PRP-1 actually consisted of two positional isomers, PIF-s, which has Asn and Asp at positions 4 and 50 respectively, and authentic PRP-1, which has the reverse arrangement. The same isomerism is present in the smaller proteins, PIF-f and PRP-3. Since the isomeric pairs have identical compositions and charges, their presence was not previously detected. Also, by using a more highly purified preparation, it has been found that position 50 in PRP-2 and PRP-4 is Asp, rather than Asn previously reported. These new findings for the six PRPs define their complete primary structures, which are now consistent with those proposed for PRP-1 and PIF-s from cDNA data, and are also consistent with the chromatographic and electrophoretic behaviours of the six PRPs and their derived peptides. These corrected structures are important for understanding the biological functions and activities of these unusual proteins.
| S-EPMC1135184 | biostudies-other
Project description:Tannins are often cited for antinutritional effects, including chelation of non-heme iron. Despite this, studies exploring non-heme iron bioavailability inhibition with long-term consumption have reported mixed results. Salivary proline-rich proteins (PRPs) may mediate tannin-antinutritional effects on non-heme iron bioavailability.To review evidence regarding biochemical binding mechanisms and affinity states between PRPs and tannins, as well as effects of PRPs on non-heme iron bioavailability with tannin consumption in vivo.Narrative systematic review and meta-analysis. Common themes in biochemical modeling and affinity studies were collated for summary and synthesis; data were extracted from in vivo experiments for meta-analysis.Thirty-two studies were included in analysis. Common themes that positively influenced tannin-PRP binding included specificity of tannin-PRP binding, PRP and tannin stereochemistry. Hydrolyzable tannins have different affinities than condensed tannins when binding to PRPs. In vivo, hepatic iron stores and non-heme iron absorption are not significantly affected by tannin consumption (d = -0.64-1.84; -2.7-0.13 respectively), and PRP expression may increase non-heme iron bioavailability with tannin consumption.In vitro modeling suggests that tannins favor PRP binding over iron chelation throughout digestion. Hydrolyzable tannins are not representative of tannin impact on non-heme iron bioavailability in food tannins because of their unique structural properties and PRP affinities. With tannin consumption, PRP production is increased, and may be an initial line of defense against tannin-non-heme iron chelation in vivo. More research is needed to compare competitive binding of tannin-PRP to tannin-non-heme iron complexes, and elucidate PRPs' role in adaption to non-heme iron bioavailability in vivo.
| S-EPMC5525358 | biostudies-other
Project description:PurposeGluten proteins, the culprits in celiac disease (CD), show striking similarities in primary structure with human salivary proline-rich proteins (PRPs). Both are enriched in proline and glutamine residues that often occur consecutively in their sequences. We investigated potential differences in the spectrum of salivary PRPs in health and CD.Experimental designStimulated salivary secretions were collected from CD patients, patients with refractory CD, patients with gastrointestinal complaints but no CD, and healthy controls. PRP isoforms/peptides were characterized by anionic and SDS-PAGE, PCR, and LC-ESI-MS.ResultsThe gene frequencies of the acidic PRP isoforms PIF, Db, Pa, PRP1, and PRP2 did not differ between groups. At the protein level, PRPs peptides showed minor group differences, but these could not differentiate the CD and/or refractory CDs groups from the controls.Conclusions and clinical relevanceThis extensive study established that salivary PRPs, despite similarity to gluten proteins, show no apparent correlation with CD and thus will not serve as diagnostic markers for the disease. The structural basis for the tolerance to the gluten-like PRP proteins in CD is worthy of further exploration and may lead to the development of gluten-like analogs lacking immunogenicity that could be used therapeutically.
| S-EPMC4551613 | biostudies-literature
Project description:ARID1A and PGR plays an important role in embryo implantation and decidualization during early pregnancy. Uterine specific Arid1a knockout (Pgrcre/+Arid1af/f ) mice exhibit in non-receptive endometrium at day 3.5 of gestation (GD 3.5). In previous studies, using transcriptomic analysis in the uterus of Pgrcre/+Arid1af/f mice, we identified proline-rich acidic protein 1 (PRAP1) as one of the down-regulated genes by ARID1A in the uterus. In the present study, we performed RT-qPCR and immunohistochemistry analysis to investigate the regulation of PRAP1 by ARID1A and determine expression patterns of PRAP1 in the uterus during early pregnancy. During early pregnancy, PRAP1 expression was strong at day 0.5 of gestation (GD 0.5) and then decreased at GD 3.5 in the epithelium and stroma. After implantation, PRAP1 expression was remarkably reduced in the uterus. However, the expression of PRAP1 at GD 3.5 was remarkably increased in the Pgrcre/+Arid1a f/f mice. To determine the ovarian steroid hormone regulation of PRAP1, we examined the expression of PRAP1 in ovariectomized control, Pgrcre/+Arid1af/f , and progesterone receptor knock-out (PRKO) mice treated with progesterone. While PRAP1 proteins were strongly expressed in the luminal and glandular epithelium of control mice treated with vehicle, progesterone treatment suppressed the expression of PRAP1. However, PRAP1 was not suppressed in both the Pgrcre/+Arid1af/f and PRKO mice compared to controls. Our results identified PRAP1 as a novel target of ARID1A and PGR in the murine uterus.
| S-EPMC6812973 | biostudies-literature