1EW9

ALKALINE PHOSPHATASE (E.C. 3.1.3.1) COMPLEX WITH MERCAPTOMETHYL PHOSPHONATE

Summary for 1EW9

• Entry DOI: 10.2210/pdb1ew9/pdb
• Related: 1B8J 1EW8
• Descriptor: ALKALINE PHOSPHATASE, ZINC ION, SULFATE ION, ... (6 entities in total)
• Functional Keywords: enzyme-inhibitor complex, hydrolase
• Biological source: Escherichia coli
• Cellular location: Periplasm: P00634
• Total number of polymer chains: 2
• Total formula weight: 95074.13

Authors

Holtz, K.M.,Stec, B.,Meyers, J.K.,Antonelli, S.M.,Widlanski, T.S.,Kantrowitz, E.R. (deposition date: 2000-04-24, release date: 2002-05-01, Last modification date: 2024-03-13)

Primary citation

Holtz, K.M.,Stec, B.,Myers, J.K.,Antonelli, S.M.,Widlanski, T.S.,Kantrowitz, E.R.
Alternate modes of binding in two crystal structures of alkaline phosphatase-inhibitor complexes.
Protein Sci., 9:907-915, 2000

PubMed 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.

PubMed: 10850800

Experimental method

X-RAY DIFFRACTION (2 Å)