Tags

Type your tag names separated by a space and hit enter

Intracrystalline proteins and the hidden ultrastructure of calcium oxalate urinary crystals: implications for kidney stone formation.
J Struct Biol. 2001 Apr; 134(1):5-14.JS

Abstract

The external appearance of urinary calcium oxalate (CaOx) crystals suggests that they are solid, homogeneous structures, despite their known association with proteins. Our aim was to determine whether proteins comprising the organic matrix of CaOx crystals are superficial or intracrystalline in order to clarify the role of urinary proteins in the formation of kidney stones. CaOx crystals were precipitated from centrifuged and filtered, or ultrafiltered, healthy human urine. They were then treated with dilute NaOH to remove bound proteins, partially demineralized with EDTA, or fractured and subjected to limited proteolysis before examination by low-resolution scanning electron microscopy or field emission scanning electron microscopy. Crystals precipitated from centrifuged and filtered urine had a complex interior network of protein distributed throughout the mineral phase, which appeared to comprise closely packed subcrystalline particles stacked in an orderly array among an amorphous organic matrix. This ultrastructure was not evident in crystals deposited in the absence of macromolecules, which were completely solid. This is the first direct evidence that crystals generated from cell-free systems contain significant amounts of protein distributed throughout a complex internal cribriform ultrastructure. Combined with mineral erosion in the acidic lysosomal environment, proteins inside CaOx crystals would render them susceptible to attack by urinary and intracellular renal proteases and facilitate their further dissolution or disruption into small particles and ions for removal by exocytosis. The findings also have broader ramifications for industry and the materials sciences, as well as the development and resorption of crystals in biomineralization systems throughout nature.

Authors+Show Affiliations

Department of Surgery, Flinders University School of Medicine, Bedford Park, South Australia, 5042, Australia. rose.ryall@flinders.edu.auNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

11469872

Citation

Lyons Ryall, R, et al. "Intracrystalline Proteins and the Hidden Ultrastructure of Calcium Oxalate Urinary Crystals: Implications for Kidney Stone Formation." Journal of Structural Biology, vol. 134, no. 1, 2001, pp. 5-14.
Lyons Ryall R, Fleming DE, Doyle IR, et al. Intracrystalline proteins and the hidden ultrastructure of calcium oxalate urinary crystals: implications for kidney stone formation. J Struct Biol. 2001;134(1):5-14.
Lyons Ryall, R., Fleming, D. E., Doyle, I. R., Evans, N. A., Dean, C. J., & Marshall, V. R. (2001). Intracrystalline proteins and the hidden ultrastructure of calcium oxalate urinary crystals: implications for kidney stone formation. Journal of Structural Biology, 134(1), 5-14.
Lyons Ryall R, et al. Intracrystalline Proteins and the Hidden Ultrastructure of Calcium Oxalate Urinary Crystals: Implications for Kidney Stone Formation. J Struct Biol. 2001;134(1):5-14. PubMed PMID: 11469872.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intracrystalline proteins and the hidden ultrastructure of calcium oxalate urinary crystals: implications for kidney stone formation. AU - Lyons Ryall,R, AU - Fleming,D E, AU - Doyle,I R, AU - Evans,N A, AU - Dean,C J, AU - Marshall,V R, PY - 2001/7/27/pubmed PY - 2002/1/29/medline PY - 2001/7/27/entrez SP - 5 EP - 14 JF - Journal of structural biology JO - J Struct Biol VL - 134 IS - 1 N2 - The external appearance of urinary calcium oxalate (CaOx) crystals suggests that they are solid, homogeneous structures, despite their known association with proteins. Our aim was to determine whether proteins comprising the organic matrix of CaOx crystals are superficial or intracrystalline in order to clarify the role of urinary proteins in the formation of kidney stones. CaOx crystals were precipitated from centrifuged and filtered, or ultrafiltered, healthy human urine. They were then treated with dilute NaOH to remove bound proteins, partially demineralized with EDTA, or fractured and subjected to limited proteolysis before examination by low-resolution scanning electron microscopy or field emission scanning electron microscopy. Crystals precipitated from centrifuged and filtered urine had a complex interior network of protein distributed throughout the mineral phase, which appeared to comprise closely packed subcrystalline particles stacked in an orderly array among an amorphous organic matrix. This ultrastructure was not evident in crystals deposited in the absence of macromolecules, which were completely solid. This is the first direct evidence that crystals generated from cell-free systems contain significant amounts of protein distributed throughout a complex internal cribriform ultrastructure. Combined with mineral erosion in the acidic lysosomal environment, proteins inside CaOx crystals would render them susceptible to attack by urinary and intracellular renal proteases and facilitate their further dissolution or disruption into small particles and ions for removal by exocytosis. The findings also have broader ramifications for industry and the materials sciences, as well as the development and resorption of crystals in biomineralization systems throughout nature. SN - 1047-8477 UR - https://www.unboundmedicine.com/medline/citation/11469872/Intracrystalline_proteins_and_the_hidden_ultrastructure_of_calcium_oxalate_urinary_crystals:_implications_for_kidney_stone_formation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1047-8477(01)94363-1 DB - PRIME DP - Unbound Medicine ER -