PDBsum entry: 1ew9

Hydrolase

PDB id: 1ew9

Contents

Protein chains

449 a.a. *

Ligands

SO4 ×2

MMQ ×2

Metals

_ZN ×6

_MG ×2

Waters ×557

* Residue conservation analysis

PDB id:

1ew9

Name:

Hydrolase

Title:

Alkaline phosphatase (E.C. 3.1.3.1) complex with mercaptomet phosphonate

Structure:

Alkaline phosphatase. Chain: a, b. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Strain: sm547. Cellular_location: periplasm. Gene: phoa. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Dimer (from PQS)

Resolution:

2.00Å R-factor: 0.181 R-free: 0.229

Authors:

K.M.Holtz,B.Stec,J.K.Meyers,S.M.Antonelli,T.S.Widlanski, E.R.Kantrowitz

Key ref:

K.M.Holtz et al. (2000). Alternate modes of binding in two crystal structures of alkaline phosphatase-inhibitor complexes. Protein Sci, 9, 907-915. PubMed id: 10850800 Ref: Full text

Date:

24-Apr-00 Release date: 01-May-02

Protein chains

P00634  (PPB_ECOLI) -  Alkaline phosphatase

Seq: 471 a.a.

Struc: 449 a.a.

Enzyme reactions

• Enzyme class: E.C.3.1.3.1 - Alkaline phosphatase.
• Reaction: A phosphate monoester + H₂O = an alcohol + phosphate

phosphate monoester + H(2)O = alcohol + phosphate (Bound ligand (Het Group name = MMQ) matches with 57.14% similarity)

• Cofactor: Magnesium; Zinc

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

 Gene Ontology (GO) functional annotation 

• Cellular component: periplasmic space (1 term)
• Biological process: metabolic process (2 terms)
• Biochemical function: catalytic activity (10 terms)

reference

Full text	Protein Sci 9:907-915 (2000)
PubMed id: 10850800

Alternate modes of binding in two crystal structures of alkaline phosphatase-inhibitor complexes.

K.M.Holtz, B.Stec, J.K.Myers, S.M.Antonelli, T.S.Widlanski, E.R.Kantrowitz.

ABSTRACT

Two high resolution crystal structures of Escherichia coli alkaline phosphatase (AP) in the presence of phosphonate inhibitors are reported. The phosphonate compounds, phosphonoacetic acid (PAA) and mercaptomethylphosphonic acid (MMP), bind competitively to AP with dissociation constants of 5.5 and 0.6 mM, respectively. The structures of the complexes of AP with PAA and MMP were refined at high resolution to crystallographic R-values of 19.0 and 17.5%, respectively. Refinement of the AP-inhibitor complexes was carried out using X-PLOR. The final round of refinement was done using SHELXL-97. Crystallographic analyses of the inhibitor complexes reveal different binding modes for the two phosphonate compounds. The significant difference in binding constants can be attributed to these alternative binding modes observed in the high resolution X-ray structures. The phosphinyl group of PAA coordinates to the active site zinc ions in a manner similar to the competitive inhibitor and product inorganic phosphate. In contrast, MMP binds with its phosphonate moiety directed toward solvent. Both enzyme-inhibitor complexes exhibit close contacts, one of which has the chemical and geometrical potential to be considered an unconventional hydrogen bond of the type C-H...X.