1ELZ

E. COLI ALKALINE PHOSPHATASE MUTANT (S102G)

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.173 
  • R-Value Work: 0.138 
  • R-Value Observed: 0.138 

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This is version 1.3 of the entry. See complete history. 


Literature

Kinetic and X-ray structural studies of three mutant E. coli alkaline phosphatases: insights into the catalytic mechanism without the nucleophile Ser102.

Stec, B., Hehir, M.J., Brennan, C., Nolte, M., Kantrowitz, E.R.

(1998) J Mol Biol 277: 647-662

  • DOI: 10.1006/jmbi.1998.1635
  • Primary Citation of Related Structures:  
    1ELZ, 1ELY, 1ELX

  • PubMed Abstract: 

    • Escherichia coli alkaline phosphatase (EC 3.1.3.1) is a non-specific phosphomonoesterase that catalyzes the hydrolysis reaction via a phosphoseryl intermediate to produce inorganic phosphate and the corresponding alcohol. We investigated the nature of the primary nucleophile, fulfilled by the deprotonated Ser102, in the catalytic mechanism by mutating this residue to glycine, alanine and cysteine ...

    Escherichia coli alkaline phosphatase (EC 3.1.3.1) is a non-specific phosphomonoesterase that catalyzes the hydrolysis reaction via a phosphoseryl intermediate to produce inorganic phosphate and the corresponding alcohol. We investigated the nature of the primary nucleophile, fulfilled by the deprotonated Ser102, in the catalytic mechanism by mutating this residue to glycine, alanine and cysteine. The efficiencies of the S102G, S102A and S102C enzymes were 6 x 10(5)-fold, 10(5)-fold and 10(4)-fold lower than the wild-type enzyme, respectively, as measured by the kcat/Km ratio, still substantially higher than the non-catalyzed reaction. In order to investigate the structural details of the altered active site, the enzymes were crystallized and their structures determined. The enzymes crystallized in a new crystal form corresponding to the space group P6322. Each structure has phosphate at each active site and shows little departure from the wild-type model. For the S102G and S102A enzymes, the phosphate occupies the same position as in the wild-type enzyme, while in the S102C enzyme it is displaced by 2.5 A. This kinetic and structural study suggests an explanation for differences in catalytic efficiency of the mutant enzymes and provides a means to study the nature and strength of different nucleophiles in the same environment. The analysis of these results provides insight into the mechanisms of other classes of phosphatases that do not utilize a serine nucleophile.

    Related Citations: 
    • Reaction Mechanism of Alkaline Phosphatase Based on Crystal Structures. Two-Metal Ion Catalysis
      Kim, E.E., Wyckoff, H.W.
      (1991) J Mol Biol 218: 449
    Organizational Affiliation: 

    Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02167, USA.



Macromolecules
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(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ALKALINE PHOSPHATASEA, B449Escherichia coliMutation(s): 1 
Gene Names: phoA
EC: 3.1.3.1
Find proteins for P00634 (Escherichia coli (strain K12))
Explore P00634 
Go to UniProtKB:  P00634
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.173 
  • R-Value Work: 0.138 
  • R-Value Observed: 0.138 
  • Space Group: P 63 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 164.57α = 90
b = 164.5β = 90
c = 138.59γ = 120
Software Package:
Software NamePurpose
XDSdata scaling
XDSdata reduction
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-05-27
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2011-11-16
    Changes: Atomic model