Evolutionary and Structural Analyses of Mammalian Haloacid Dehalogenase-type Phosphatases AUM and Chronophin Provide Insight into the Basis of Their Different Substrate Specificities |
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Authors: | Annegrit Seifried Gunnar Knobloch Prashant S Duraphe Gabriela Segerer Julia Manhard Hermann Schindelin J?rg Schultz Antje Gohla |
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Institution: | From the ‡Institute for Pharmacology and Toxicology.;§Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, 97080 Würzburg and ;the ¶Biocenter, Department of Bioinformatics, University of Würzburg, 97074 Würzburg, Germany |
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Abstract: | Mammalian haloacid dehalogenase (HAD)-type phosphatases are an emerging family of phosphatases with important functions in physiology and disease, yet little is known about the basis of their substrate specificity. Here, we characterize a previously unexplored HAD family member (gene annotation, phosphoglycolate phosphatase), which we termed AUM, for aspartate-based, ubiquitous, Mg2+-dependent phosphatase. AUM is a tyrosine-specific paralog of the serine/threonine-specific protein and pyridoxal 5′-phosphate-directed HAD phosphatase chronophin. Comparative evolutionary and biochemical analyses reveal that a single, differently conserved residue in the cap domain of either AUM or chronophin is crucial for phosphatase specificity. We have solved the x-ray crystal structure of the AUM cap fused to the catalytic core of chronophin to 2.65 Å resolution and present a detailed view of the catalytic clefts of AUM and chronophin that explains their substrate preferences. Our findings identify a small number of cap domain residues that encode the different substrate specificities of AUM and chronophin. |
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Keywords: | Molecular Evolution Pyridoxal Phosphate Serine/Threonine Protein Phosphatase Tyrosine-Protein Phosphatase (Tyrosine Phosphatase) X-ray Crystallography Haloacid Dehalogenase Phosphatase Phosphatase Substrate Specificity Phosphoglycolate Phosphatase |
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