Intestine calcium binding protein

Calcium-binding protein is not found in the intestinal mucosa of vitamin D-deficient animals. It is synthesized only in response to the presence of a material with vitamin D activity. Thus, using antisemm specific to intestinal calcium-binding protein, a radioimmunodiffusion assay (98) conducted on ... 

Nonrepetitive but well-defined structures of this type form many important features of enzyme active sites. In some cases, a particular arrangement of coil structure providing a specific type of functional site recurs in several functionally related proteins. The peptide loop that binds iron-sulfur clusters in both ferredoxin and high potential iron protein is one example. Another is the central loop portion of the E—F hand structure that binds a calcium ion in several calcium-binding proteins, including calmodulin, carp parvalbumin, troponin C, and the intestinal calcium-binding protein. This loop, shown in Figure 6.26, connects two short a-helices. The calcium ion nestles into the pocket formed by this structure. 

GFP hopo ICBP IP3 Ln3+ mal memal MLCK nota oxine par pdta pmea py quin-2 green fluorescent protein hydroxypyridinon(at)e intestinal calcium-binding protein inositol 1,4,5-triphosphate a lanthanide(III) cation malonate methylmalonate myosin light chain kinase 1,4,7-triazacyclononane-l,4,7-triacetate 8- hydroxyquinoline pyridine-2-azo-4 -dimethylaniline propylene-1,2-diaminetetraacetate 9- [2-(phosphonomethoxy)ethyl] adenine pjrridine pjrridyl 8-amino-2- [(2-amino-5-methylphenoxy )methyl] -6-methoxyquinoline-ATJV -tetraacetate 2- [ [2-[his(carboxymethyl)amino]-5-methyl-phenoxy] methyl] -6-methoxy-8- [bis(carboxymethyl) amino] quinoline]... 

K. Chiba, T. Ohyashiki, and T. Mohri, Quantitative analysis of calcium binding to porcine intestinal calcium-binding protein, J. Biochem. (Tokyo) 93, 487-493 (1983). 

J. D. O Neil, K. J. Dorrington, and T. Hofmann, Luminescence and circular-dichroism analysis of terbium binding by pig intestinal calcium-binding protein (relative mass = 9000), Can. J. Biochem. Cell Biol. 62, 434M42 (1984). 

In order to understand these effects in a detailed way for the calcium-binding proteins, it is necessary to compare the structure of the calcium-free and calcium-bound forms of each protein. The structures of parvalbumin and the intestinal calcium-binding protein (Wasserman protein) are known (see Table 6), but at present there are no crystal structures available for calcium-free proteins. Some structural information has been deduced from changes in the NMR spectrum as calcium is removed from the calcium-bound proteins.209,210... 

The arrangement of the proteins within the membrane seems to depend to some extent on the electrostatic surface potential and interface permittivity. It is influenced by electrostatic interaction between the proteins, polar head groups of the phospholipid and ions within the aqueous medium of the membrane surface. This can be affected by exogenous molecules such as drugs. Phospholipid-induced conformational change in intestinal calcium-binding protein in the absence and presence of Ca2+ has been described [37]. There is, however, no doubt that hydrophobic interactions between peptides and membrane interfaces play an important role. A general frame-... 

The amino acid analysis of chick intestinal calcium-binding protein revealed a high content of aspartic and glutamic acids and lysine. These features are common to all low molecular calcium-binding proteins. 

Norman (152) in 1977 reported that la,24(i ),25-trihydroxyvitamin D3 is less potent than la,25-dihydroxyvitamin D3 in the rachitic chick in terms of its ability to stimulate intestinal calcium absorption, mobilize bone calcium, and induce intestinal calcium binding protein. DeLuca (27) had shown earlier that 24,25-dihydroxyvitamin D3 must be converted to la,24,25-trihydroxyvitamin D3 in the kidney in order to have biological activity. Gray (62) in 1974 had demonstrated presence of a peak in the analysis of the plasma of normal and nephrectomized humans given H-labeled 25-hydroxyvitamin D3, which was chromatographically similar to authentic la,24,25-trihydroxyvitamin D3. DeLuca 182) has recently shown that the renal 24-hydroxylase enzyme requires presence of a hydroxyl group be on the 25-carbon of the vitamin D3 molecule before further hydroxylation can take place. The 24(i )-hydroxylase is, however, not totally isolated in the kidney as the la-hydroxylase appears to be. DeLuca 182) finds that nephrectomized animals also metabolize la,25-dihydroxyvitamin D3 to la,24(i ),25-trihydroxyvitamin D3. 

We obtained atomic coordinates for modelling studies on carp parvalbumin, bovine-intestinal calcium binding protein, and also troponin-C (for which only the a-carbons are available at present) from the Brookhaven Protein Data Bank (October, 1985 release). The molecular graphics package used was Chemgraf (January, 1985 release), running on a VAX 11/780 at NUMAC, and the display was on a Sigma 5688 terminal. 

Calbindin Dg, previously known as intestinal calcium binding protein, is the smallest (75 amino acids) in the calmodulin superfamily of proteins. A special characteristic of this EF-hand protein is that the first metal binding loop is modified compared to the typical EF-hand loop, a pseudo EF-hand, a common feature for... 

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