Failure to detect an amorphous calcium-phosphate solid phase in bone mineral: A radial distribution function study

1984 ◽  
Vol 36 (1) ◽  
pp. 291-301 ◽  
Author(s):  
Marc D. Grynpas ◽  
Laurence C. Bonar ◽  
Melvin J. Glimcher
Keyword(s):  
Distribution Function ◽  
Calcium Phosphate ◽  
Radial Distribution Function ◽  
Bone Mineral ◽  
Radial Distribution ◽  
Amorphous Calcium Phosphate ◽  
Solid Phase ◽  
Function Study

Recent studies of the mineral phase in bone and its possible linkage to the organic matrix by protein-bound phosphate bonds

1984 ◽  
Vol 304 (1121) ◽  
pp. 479-508 ◽  
Keyword(s):  
Calcium Phosphate ◽  
Bone Mineral ◽  
Amorphous Calcium Phosphate ◽  
Solid Phase ◽  
Function Analysis ◽  
Bone Matrix ◽  
Organic Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineralized Tissues

The most widely accepted hypothesis to account for maturational changes in the X-ray diffraction characteristics of bone mineral has been the ‘amorphous calcium phosphate theory’, which postulates that an initial amorphous calcium phosphate solid phase is deposited that gradually converts to poorly crystalline hydroxyapatite. Our studies of bone mineral of different ages by X-ray radial distribution function analysis and 31 P n.m.r. have conclusively demonstrated that a solid phase of amorphous calcium phosphate does not exist in bone in any significant amount. 31 P n.m.r. studies have detected the presence of acid phosphate groups in a brushite-like configuration. Phosphoproteins containing O -phosphoserine and O -phosphothreonine have been isolated from bone matrix and characterized. Tissue and cell culture have established that they are synthesized in bone, most likely by the osteoblasts. Physicochemical and pathophysiological studies support the thesis that the mineral and organic phases of bone and other vertebrate mineralized tissues are linked by the phosphomonester bonds of O -phosphoserine and O -phosphothreonine, which are constituents of both the structural organic matrix and the inorganic calcium phosphate crystals.

The Influence of Hydrogen atoms on the Performance of Radial Distribution Function Based Descriptors in the Chemoinformatic Studies of HIV-1 Prote-ase Complexes with Inhibitors.

2020 ◽  
Vol 17 ◽  
Author(s):  
Jurica Novak ◽  
Maria A. Grishina ◽  
Vladimir A. Potemkin
Keyword(s):  
Distribution Function ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Current Model ◽  
Direct Interaction ◽  
Hydroxyl Group ◽  
Linear Regression Method ◽  
Hydrogen Atoms ◽  
Protease Enzyme ◽  
Hiv 1

: In this letter the newly introduced approach based on the radial distribution function (RDF) weighted by the number of va-lence shell electrons is applied for a series of HIV-1 protease enzyme and its complexes with inhibitors to evaluate the influ-ence of hydrogen atoms on the performance of the model. The multiple linear regression method was used for the selection of the relevant descriptors. Two groups of residues having dominant contribution to the RDF descriptor are identified as relevant for the inhibition. In the first group are residues like Arg8, Asp25, Thr26, Gly27 and Asp29, which establish direct interaction with the inhibitor, while the second group consists of the amino acids at the interface of the two homodimer sub-units or with the solvent. The crucial motif pointed out by our approach as the most important for inhibition of the enzyme’s activity and present in all inhibitors is hydroxyl group that establish hydrogen bond with Asp25 side chain. Additionally, the comparison to the model without hydrogen showed that both models are of similar quality, but the downside of the current model is the need for the determination of residues’ protonation states.

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