Deganello S
Nephrology Program, University of Chicago, IL 60637.
Calcif Tissue Int. 1991 Jun;48(6):421-8. doi: 10.1007/BF02556456.
Study of crystals of calcium oxalate monohydrate grown from gels exposed to 0, 5.6x, 12.5x, 26.2x, 52.5x, 100x, 200 x 10(-7) M nephrocalcin indicate that this protein profoundly affects their habit, size, and crystal structure. By the time nephrocalcin concentration is 26.2 x 10(-7) M calcium oxalate monohydrate undergoes a phase change in its basic structure and both crystal size as well the resolution of its diffraction pattern are severely curtailed. These effects are magnified when the protein is 52.5 x 10(-7) M, since long-range disorder becomes extreme and, out of the entire diffraction pattern, only the 0k0's, h00's and a few other nonaxial reflections remain from the ordered part of the crystal structure. Finally, once the concentration of nephrocalcin is raised to 100 and 200 x 10(-7) M, growth is so inhibited that calcium oxalate monohydrate no longer grows as distinct individuals but rather as aggregates of very small crystallites. All of this is caused by the ability on the part of nephrocalcin to disturb the juxtaposition of the (101) layers along c by disrupting the organization of both the C(3)-C(4) oxalate groups and the water molecules. Such interaction is modulated by the efficiency with which nephrocalcin adsorbs upon the (101) planes; this process is stereospecific.
对从暴露于浓度为0、5.6x、12.5x、26.2x、52.5x、100x、200 x 10(-7) M肾钙素的凝胶中生长出来的一水合草酸钙晶体的研究表明，这种蛋白质对其晶习、尺寸和晶体结构有深远影响。当肾钙素浓度达到26.2 x 10(-7) M时，一水合草酸钙的基本结构发生相变，晶体尺寸及其衍射图谱的分辨率都严重降低。当蛋白质浓度为52.5 x 10(-7) M时，这些影响会被放大，因为长程无序变得极为严重，在整个衍射图谱中，晶体结构的有序部分仅剩下0k0、h00以及其他一些非轴向反射。最后，一旦肾钙素浓度提高到100和200 x 10(-7) M，生长受到如此抑制，以至于一水合草酸钙不再以独立个体生长，而是以非常小的微晶聚集体形式生长。所有这些都是由肾钙素通过破坏草酸根C(3)-C(4)基团和水分子的排列来干扰(101)层沿c轴的并置能力所导致的。这种相互作用由肾钙素在(101)平面上的吸附效率调节；这个过程具有立体特异性。
