tailieunhanh - Báo cáo khoa học: Role of calcium phosphate nanoclusters in the control of calcification

Calcium phosphate nanoclusters are equilibrium particles of defined chemi-cal composition in which a core of amorphous calcium phosphate is sequestered within a shell of casein phosphopeptides. Sequence analyses and a structure prediction method were applied to secreted phosphopro-teins of known importance in controlling calcification, and eight noncasein phosphoproteins were identified as containing one or more subsequences capable of forming nanoclusters. | Role of calcium phosphate nanoclusters in the control of calcification Carl Holt1 Esben S. S0rensen2 and Roger A. Clegg1 1 Hannah Research Institute Ayr UK 2 Protein Chemistry Laboratory Department of Molecular Biology University of Arhus Denmark Keywords casein dentin matrix acidic phosphoprotein 1 fetuin natively unfolded protein osteopontin Correspondence C. Holt 47 Logan Drive Troon KA10 6PN UK Tel 44 1292 317 615 E-mail cholt002@ Received 21 November 2008 revised 17 January 2009 accepted 11 February 2009 doi Calcium phosphate nanoclusters are equilibrium particles of defined chemical composition in which a core of amorphous calcium phosphate is sequestered within a shell of casein phosphopeptides. Sequence analyses and a structure prediction method were applied to secreted phosphoproteins of known importance in controlling calcification and eight noncasein phosphoproteins were identified as containing one or more subsequences capable of forming nanoclusters. Small-angle X-ray scattering was used to confirm that a plasmin phosphopeptide of one of the identified proteins osteopontin formed a novel type of calcium phosphate nanocluster in which the radius of the amorphous calcium phosphate core was four times larger than is typical of casein nanoclusters. A thermodynamic treatment of nanocluster formation identified the factors of importance in determining the equilibrium size of the core and showed how a nanocluster solution could be thermodynamically stable yet supersaturated with respect to the mineral phase of bones and teeth. It is suggested that the ability of some secreted phosphoproteins to form nanoclusters is physiologically important for the control or inhibition of calcification in soft and mineralized tissues the extracellular matrix and a wide range of biofluids including milk and blood. Many biological fluids including blood milk extracellular fluid saliva urine synovial fluid and cerebrospinal fluid .

TỪ KHÓA LIÊN QUAN
crossorigin="anonymous">
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.