D-fructose-2,6-bisphosphate 2-phosphohydrolase
Evidence for two catalytic sites on 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase. Dynamics of substrate exchange and phosphoryl enzyme formation.
Mechanism of activation of fructose-2,6-bisphosphatase by cAMP-dependent protein kinase.
Catalytic site of rat liver and bovine heart fructose-6-phosphate,2-kinase:fructose-2,6-bisphosphatase. Identification of fructose 6-phosphate binding site.
Evolution of a bifunctional enzyme: 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase.
Rat liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. Properties of phospho- and dephospho- forms and of two mutants in which Ser32 has been changed by site-directed mutagenesis.
Glu327 is part of a catalytic triad in rat liver fructose-2,6-bisphosphatase.
Identification of transient intermediates in the bisphosphatase reaction of rat liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase by 31P-NMR spectroscopy.
Crystal structure of the rat liver fructose-2,6-bisphosphatase based on selenomethionine multiwavelength anomalous dispersion phases.
The crystal structure of the bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase reveals distinct domain homologies.
Crystal structure of a trapped phosphoenzyme during a catalytic reaction.
Site-directed mutants of rat testis fructose 6-phosphate, 2-kinase/fructose 2,6-bisphosphatase: localization of conformational alterations induced by ligand binding.
The roles of Glu-327 and His-446 in the bisphosphatase reaction of rat liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase probed by NMR spectroscopic and mutational analyses of the enzyme in the transient phosphohistidine intermediate complex.
Reaction mechanism of fructose-2,6-bisphosphatase. A mutation of nucleophilic catalyst, histidine 256, induces an alteration in the reaction pathway.
X-RAY CRYSTALLOGRAPHY (2.4 ANGSTROMS) OF MUTANT ALA-256
Crystal structure of the H256A mutant of rat testis fructose-6-phosphate,2-kinase/fructose-2,6-bisphosphatase. Fructose 6-phosphate in the active site leads to mechanisms for both mutant and wild type bisphosphatase activities.
Mechanism of the bisphosphatase reaction of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase probed by (1)H-(15)N NMR spectroscopy.
The difference in the carboxy-terminal sequence is responsible for the difference in the activity of chicken and rat liver fructose-2,6-bisphosphatase.
Involvement of the chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase sequence His444-Arg-Glu-Arg in modulation of the bisphosphatase activity by its kinase domain.
This enzyme belongs to the phosphoglycerate mutase family. There have been a number of proposed mechanisms for this phosphatase (see literature [6], [8], [9], [10], [12], [13], [14] & [15]). However, all of these proposed mechanisms are consistent in that the catalysis proceeds in the two steps, formation and hydrolysis (or breakdown) of the phosphohistidine intermediate. His256 (PDB 1bif) acts as a nucleophile, which attacks on the phosphorous atom of the target phosphate (2-phosphate of the substrate), forming the phosphohistidine intermediate. During the catalysis, the residues, Arg255, Asn262 and Arg305 (PDB 1bif), stabilize the transition state and the intermediate, by neutralizing the negative charges at the phosphate oxygens. Moreover, Glu325 (PDB 1bif) is thought to act as a pKa modulator, according to the literature [6] and [9]. In the first step of the intermediate formation, a catalytic acid protonates to the leaving group (the product, Fructose 6-phosphate). In the second step, a catalytic base activates a bound water molecule, which hydrolyze the phosphohistidine intermediate. Which residue could be the catalytic acid and base has been debated to date. Both Glu327 and His392 (PDB 1bif) have been identified as the catalytic acid and as the catalytic base activating the water for the hydrolysis (see [6], [8], [9], [10], [12], [13], [14] & [15]). The literature [6] and [8] proposed that His392 acts as the proton donor, whilst Glu327 activates the water as a general base. In contrast, the paper [9] suggested His390 play a dual role as acid/base, whilst another paper [14] proposed that Glu327 acts as acid/base.