Evolutionary and Structural Analyses of Mammalian Haloacid Dehalogenase-type Phosphatases AUM and Chronophin Provide Insight into the Basis of Their Different Substrate Specificities

• Published in: The Journal of biological chemistry Vol. 289; no. 6; pp. 3416 - 3431
• Main Authors: Seifried, Annegrit, Knobloch, Gunnar, Duraphe, Prashant S., Segerer, Gabriela, Manhard, Julia, Schindelin, Hermann, Schultz, Jörg, Gohla, Antje
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 07.02.2014; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; Crystallography, X-Ray; Enzymology; Haloacid Dehalogenase Phosphatase; Humans; Male; Mice; Molecular Evolution; Phosphatase Substrate Specificity; Phosphoglycolate Phosphatase; Phosphoprotein Phosphatases - chemistry; Phosphoprotein Phosphatases - classification; Phosphoprotein Phosphatases - genetics; Phosphoprotein Phosphatases - metabolism; Protein Structure, Tertiary; Pyridoxal Phosphate; Rats; Serine/Threonine Protein Phosphatase; Substrate Specificity; Tyrosine-Protein Phosphatase (Tyrosine Phosphatase); X-ray Crystallography; Tyrosine-Protein Phosphatase (Tyrosine Phosphatase); X-ray Crystallography; Molecular Evolution; Haloacid Dehalogenase Phosphatase; Phosphatase Substrate Specificity; Phosphoglycolate Phosphatase; Serine/Threonine Protein Phosphatase; Pyridoxal Phosphate
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M113.503359

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. Background: Substrate specificity determinants of mammalian haloacid dehalogenase (HAD) phosphatases are poorly understood. Results: AUM (aspartate-based, ubiquitous, Mg2+-dependent phosphatase) is a novel tyrosine phosphatase and paralog of the serine/threonine- and pyridoxal 5′-phosphate phosphatase chronophin. Conclusion: Conserved cap residues in AUM or chronophin determine phosphatase substrate specificity. Significance: These findings provide a starting point for structure-based development of HAD phosphatase inhibitors.