Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCrystal 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||||||
This page was last modified 19:06, 22 December 2014.