Structure of TAB5 alkaline phosphatase mutant His 135 Asp with Mg bound in the M3 site.

Experimental Data Snapshot

  • Resolution: 1.78 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.159 
  • R-Value Observed: 0.161 

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Coordination Sphere of the Third Metal Site is Essential to the Activity and Metal Selectivity of Alkaline Phosphatases.

Koutsioulis, D.Lyskowski, A.Maki, S.Guthrie, E.Feller, G.Bouriotis, V.Heikinheimo, P.

(2010) Protein Sci 19: 75

  • DOI: https://doi.org/10.1002/pro.284
  • Primary Citation of Related Structures:  
    2W5V, 2W5W, 2W5X

  • PubMed Abstract: 

    Alkaline phosphatases (APs) are commercially applied enzymes that catalyze the hydrolysis of phosphate monoesters by a reaction involving three active site metal ions. We have previously identified H135 as the key residue for controlling activity of the psychrophilic TAB5 AP (TAP). In this article, we describe three X-ray crystallographic structures on TAP variants H135E and H135D in complex with a variety of metal ions. The structural analysis is supported by thermodynamic and kinetic data. The AP catalysis essentially requires octahedral coordination in the M3 site, but stability is adjusted with the conformational freedom of the metal ion. Comparison with the mesophilic Escherichia coli, AP shows differences in the charge transfer network in providing the chemically optimal metal combination for catalysis. Our results provide explanation why the TAB5 and E. coli APs respond in an opposite way to mutagenesis in their active sites. They provide a lesson on chemical fine tuning and the importance of the second coordination sphere in defining metal specificity in enzymes. Understanding the framework of AP catalysis is essential in the efforts to design even more powerful tools for modern biotechnology.

  • Organizational Affiliation

    New England Biolabs Inc., Ipswich, Massachusetts 01938-2723, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
375Antarctic bacterium TAB5Mutation(s): 1 
Find proteins for Q9KWY4 (Antarctic bacterium TAB5)
Explore Q9KWY4 
Go to UniProtKB:  Q9KWY4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9KWY4
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.78 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.159 
  • R-Value Observed: 0.161 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.32α = 90
b = 173.02β = 90
c = 54.97γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-11-24
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance