2W5W

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

Summary for 2W5W

• Entry DOI: 10.2210/pdb2w5w/pdb
• Related: 2IUC 2W5V 2W5X
• Descriptor: ALKALINE PHOSPHATASE, ZINC ION (3 entities in total)
• Functional Keywords: psychrophiles, cold adaptation, alkaline phosphatase, hydrolase
• Biological source: ANTARCTIC BACTERIUM TAB5
• Total number of polymer chains: 2
• Total formula weight: 81333.11

Authors

Koutsioulis, D.,Lyskowski, A.,Maki, S.,Guthrie, E.,Feller, G.,Bouriotis, V.,Heikinheimo, P. (deposition date: 2008-12-15, release date: 2009-11-24, Last modification date: 2011-07-13)

Primary citation

Koutsioulis, D.,Lyskowski, A.,Maki, S.,Guthrie, E.,Feller, G.,Bouriotis, V.,Heikinheimo, P.
Coordination Sphere of the Third Metal Site is Essential to the Activity and Metal Selectivity of Alkaline Phosphatases.
Protein Sci., 19:75-, 2010

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.

PubMed: 19916164
DOI: 10.1002/PRO.284

Experimental method

X-RAY DIFFRACTION (1.79 Å)