PDBsum entry: 1nuz

Hydrolase

PDB id: 1nuz

Contents

Protein chain

329 a.a. *

Ligands

F6P

PO4 ×2

Metals

_MG ×3

Waters ×181

* Residue conservation analysis

PDB id:

1nuz

Name:

Hydrolase

Title:

Fructose-1,6-bisphosphatase complex with magnesium, fructose phosphate and phosphate

Structure:

Fructose-1,6-bisphosphatase. Chain: a. Engineered: yes

Source:

Sus scrofa. Pig. Organism_taxid: 9823. Expressed in: escherichia coli. Expression_system_taxid: 562

Biol. unit:

Tetramer (from PQS)

Resolution:

1.90Å R-factor: 0.198 R-free: 0.246

Authors:

J.Choe,C.V.Iancu,H.J.Fromm,R.B.Honzatko

Key ref:

J.Y.Choe et al. (2003). Interaction of Tl+ with product complexes of fructose-1,6-bisphosphatase. J Biol Chem, 278, 16008-16014. PubMed id: 12595529 DOI: 10.1074/jbc.M212394200

Date:

01-Feb-03 Release date: 08-Jul-03

Protein chain

P00636  (F16P1_PIG) -  Fructose-1,6-bisphosphatase 1

Seq: 338 a.a.

Struc: 329 a.a.

Enzyme reactions

• Enzyme class: E.C.3.1.3.11 - Fructose-bisphosphatase.
• Pathway: Pentose Phosphate Pathway (later stages)
• Reaction: D-fructose 1,6-bisphosphate + H₂O = D-fructose 6-phosphate + phosphate

D-fructose 1,6-bisphosphate + H(2)O = D-fructose 6-phosphate (Bound ligand (Het Group name = F6P) corresponds exactly) + phosphate (Bound ligand (Het Group name = PO4) corresponds exactly)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Biological process: metabolic process (3 terms)
• Biochemical function: catalytic activity (5 terms)

reference

DOI no: 10.1074/jbc.M212394200

J Biol Chem 278:16008-16014 (2003)

PubMed id: 12595529

Interaction of Tl+ with product complexes of fructose-1,6-bisphosphatase.

J.Y.Choe, S.W.Nelson, H.J.Fromm, R.B.Honzatko.

ABSTRACT

Fructose-1,6-bisphosphatase requires divalent cations (Mg2+, Mn2+, or Zn2+) for catalysis, but a diverse set of monovalent cations (K+, Tl+, Rb+, or NH(4)(+)) will further enhance enzyme activity. Here, the interaction of Tl+ with fructose-1,6-bisphosphatase is explored under conditions that support catalysis. On the basis of initial velocity kinetics, Tl+ enhances catalysis by 20% with a K(a) of 1.3 mm and a Hill coefficient near unity. Crystal structures of enzyme complexes with Mg2+, Tl+, and reaction products, in which the concentration of Tl+ is 1 mm or less, reveal Mg2+ at metal sites 1, 2, and 3 of the active site, but little or no bound Tl+. Intermediate concentrations of Tl+ (5-20 mm) displace Mg2+ from site 3 and the 1-OH group of fructose 6-phosphate from in-line geometry with respect to bound orthophosphate. Loop 52-72 appears in a new conformational state, differing from its engaged conformation by disorder in residues 61-69. Tl+ does not bind to metal sites 1 or 2 in the presence of Mg2+, but does bind to four other sites with partial occupancy. Two of four Tl+ sites probably represent alternative binding sites for the site 3 catalytic Mg2+, whereas the other sites could play roles in monovalent cation activation.

Selected figure(s)

Figure 2.
Fig. 2. A new conformational state for loop 52 72. The FBPase tetramer ( top) showing the R-state, engaged loop conformation. Residues 61 69, which become disordered with increasing concentrations of Tl+, are in black. Gray spheres represent F6P molecules. Active sites and ligands are not shown on the face of the tetramer hidden from view. A more detailed view (bottom) showing the proximity of residues 61 69 (main-chain ribbon in black) to metal binding site 3 (M3), P[i], and F6P. This illustration was drawn with MOLSCRIPT (40).

Figure 3.
Fig. 3. Associative mechanism for the reverse reaction of FBPase. Glu 280, which coordinates to metal M1, and Glu97, which coordinates metals M2 and M3, come from above the plane of the schematic, and are not shown here for clarity. Thin, solid lines are coordinate bonds, dotted lines represent hydrogen bonds, and dashed lines represent partial covalent bonds. A, initial product complex. The proton on Asp74 is hypothetical. The 1-O atom of F6P (coordinated to M1) is the attacking nucleophile. An oxygen atom of orthophosphate abstracts the proton from the 1-hydroxyl group of F6P. B, transition state. The leaving oxygen atom abstracts a proton from the water molecule coordinated to M3. That same water molecule in turn accepts a proton from Asp74. C, penultimate complex. Transfer of the proton from the 1-phosphoryl group to the hydroxide anion, bridging M2 and M3, generates F16P[2] and water.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2003, 278, 16008-16014) copyright 2003.

Figures were selected by an automated process.