1eyj

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spinqualitylabelsall models 1eyj, resolution 2.28Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

FRUCTOSE-1,6-BISPHOSPHATASE COMPLEX WITH AMP, MAGNESIUM, FRUCTOSE-6-PHOSPHATE AND PHOSPHATE (T-STATE)

Overview

Crystal structures of metal-product complexes of fructose 1, 6-bisphosphatase (FBPase) reveal competition between AMP and divalent, cations. In the presence of AMP, the Zn(2+)-product and Mg(2+)-product, complexes have a divalent cation present only at one of three metal, binding sites (site 1). The enzyme is in the T-state conformation with a, disordered loop of residues 52-72 (loop 52-72). In the absence of AMP, the, enzyme crystallizes in the R-state conformation, with loop 52-72, associated with the active site. In structures without AMP, three, metal-binding sites are occupied by Zn(2+) and two of three metal sites, (sites 1 and 2) by Mg(2+). Evidently, the association of AMP with FBPase, disorders loop 52-72, the consequence of which is the release of cations, from two of three metal binding sites. In the Mg(2+) complexes (but not, the Zn(2+) complexes), the 1-OH group of fructose 6-phosphate (F6P), coordinates to the metal at site 1 and is oriented for a nucleophilic, attack on the bound phosphate molecule. A mechanism is presented for the, forward reaction, in which Asp74 and Glu98 together generate a hydroxide, anion coordinated to the Mg(2+) at site 2, which then displaces F6P., Development of negative charge on the 1-oxygen of F6P is stabilized by its, coordination to the Mg(2+) at site 1.

About this Structure

1EYJ is a Single protein structure of sequence from Sus scrofa with F6P, MG, PO4 and AMP as ligands. Active as Fructose-bisphosphatase, with EC number 3.1.3.11 Full crystallographic information is available from OCA.

Reference

Crystal structures of fructose 1,6-bisphosphatase: mechanism of catalysis and allosteric inhibition revealed in product complexes., Choe JY, Fromm HJ, Honzatko RB, Biochemistry. 2000 Jul 25;39(29):8565-74. PMID:10913263

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