A model of the transition state in the alkaline phosphatase reaction.
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Holtz KM, Stec B, Kantrowitz ER
A model of the transition state in the alkaline phosphatase reaction.
J Biol Chem. 1999 Mar 26;274(13):8351-4.
- PubMed ID
- 10085061 [ View in PubMed]
- Abstract
A high resolution crystal structure of Escherichia coli alkaline phosphatase in the presence of vanadate has been refined to 1.9 A resolution. The vanadate ion takes on a trigonal bipyramidal geometry and is covalently bound by the active site serine nucleophile. A coordinated water molecule occupies the axial position opposite the serine nucleophile, whereas the equatorial oxygen atoms of the vanadate ion are stabilized by interactions with both Arg-166 and the zinc metal ions of the active site. This structural complex supports the in-line displacement mechanism of phosphomonoester hydrolysis by alkaline phosphatase and provides a model for the proposed transition state in the enzyme-catalyzed reaction.