Alkaline phosphatase structure

Alkaline phosphatase, 2,774 mechanism, 6,612 metal substitution, 6,611 structure, 6,611 zinc, 5.1006 6,610 Alkanes... 

Two dinuclear complexes, with five-coordinate zinc centers, derived from tris((2-pyridyl)-methyl) amine were synthesized and bridging phosphate or phosphate ester groups. The X-ray structure of the phosphate monoester complex shows a syn-anti bridging mode in contrast to alkaline phosphatase in which it is syn-syn 448 Fenton and co-workers have also studied other related dizinc species of compartmental ligands 449... 

Figure 1.13 The a-chain structure of alkaline phosphatase illustrates the complex nature of polypeptide structure within proteins (Kim and Wyckoff, 1991).

Plant Cells and Tissues Structure-Function Relationships. Methods for the Cytochemical/Histochemical Localization of Plant Cell/Tissue Chemicals. Methods in Light Microscope Radioautography. Some Fluorescence Microscopical Methods for Use with Algal, Fungal, and Plant Cells. Fluorescence Microscopy of Aniline Blue Stained Pistils. A Short Introduction to Immunocytochemistry and a Protocol for Immunovi-sualization of Proteins with Alkaline Phosphatase. The Fixation of Chemical Forms on Nitrocellulose Membranes. Dark-Field Microscopy and Its Application to Pollen Tube Culture. Computer-Assisted Microphotometry. Isolation and Characterization of... 

It was clear for some time that a number of zinc enzymes required two or more metal ions for full activity, but in the absence of X-ray structural data the location of these metal centres with regard to one another was often uncertain. When the first 3-D structures began to appear, it became clear that the metals were in close proximity. A particular feature of many of these enzymes was the presence of a bridging ligand between two of the metal sites, usually an Asp residue of the protein, which is occasionally replaced by a water molecule. While some of the sites contain only Zn ions, several contain Zn in combination with Cu (in cytosolic superoxide dismutases) Fe (in purple acid phosphatases) or Mg (in alkaline phosphatase and the aminopeptidase of lens). 

Several zinc enzymes that catalyse the hydrolysis of phosphoesters have catalytic sites, which contain three metal ions in close proximity (3-7 A from each other). These include (Figure 12.11) alkaline phosphatase, phospholipase C and nuclease PI. In phospholipase C and nuclease PI, which hydrolyse phosphatidylcholine and single-stranded RNA (or DNA), respectively, all three metal ions are Zn2+. However, the third Zn2+ ion is not directly associated with the dizinc unit. In phospholipase C, the Zn-Zn distance in the dizinc centre is 3.3 A, whereas the third Zn is 4.7 and 6.0 A from the other two Zn2+ ions. All three Zn2+ ions are penta-coordinate. Alkaline phosphatase, which is a non-specific phos-phomonoesterase, shows structural similarity to phospholipase C and PI nuclease however,... 

Golgi, in early neuroanatomical studies (1898) staining neurones by silver impregnation, observed a reticular apparatus which was crescent shaped and appeared to be linked through canaliculi. The structure was also seen in secretory cells. Between 1949 and 1954, Baker reported the presence of similar systems in unfixed cells examined by phase contrast. The structures could be stained by osmium tetroxide and probably contained lipid. They also stained for glycoprotein and alkaline phosphatase. Baker s confirmation of the existence of the... 

J. E. Coleman, P. Gettins, Alkaline Phosphatase, Solution Structure and Mechanism , Adv. Enzymol. Relat. Areas Mol. Biol. 1983, 55, 381-452. 

Currently, only a handful of examples of unique protein carboxylate-zinc interactions are available in the Brookhaven Protein Data Bank. Each of these entries, however, displays syn coordination stereochemistry, and two are bidentate (Christianson and Alexander, 1989) (Fig. 5). Other protein structures have been reported with iyw-oriented car-boxylate-zinc interactions, but full coordinate sets are not yet available [e.g., DNA polymerase (Ollis etal., 1985) and alkaline phosphatase (Kim and Wyckoff, 1989)]. A survey of all protein-metal ion interactions reveals that jyw-carboxylate—metal ion stereochemistry is preferred (Chakrabarti, 1990a). It is been suggested that potent zinc enzyme inhibition arises from syn-oriented interactions between inhibitor carboxylates and active-site zinc ions (Christianson and Lipscomb, 1988a see also Monzingo and Matthews, 1984), and the structures of such interactions may sample the reaction coordinate for enzymatic catalysis in certain systems (Christianson and Lipscomb, 1987). 

---