The crystal structure of a low-molecular-weight phosphotyrosine phosphatase

来自 EBSCO

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作者：

XD Su，N Taddei，M Stefani，G Ramponi，Pr Nordlund

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摘要：

PROTEIN tyrosine phosphorylation and dephosphorylation are central reactions for control of cellular division, differentiation and development 1 . Here we describe the crystal structure of a low-molecular-weight phosphotyrosine protein phosphatase (PTPase) 2 , a cytosolic phosphatase present in many mammalian cells. The enzyme catalyses the dephosphorylation of phosphotyrosine-containing substrates 3–6 and overexpression of the protein in normal and transformed cells inhibits cell proliferation 7,8 . The structure of the low-molecular-weight PTPase reveals an α/β protein containing a phosphate-binding loop motif at the amino end of helix αl. This motif includes the essential active-site residues Cys 12 and Arg 18 and bears striking similarities to the active-site motif recently described in the structure of human PTP1B 9 . The structure of the low-molecular-weight PTPase supports a reaction mechanism involving the conserved Cys 12 as an attacking nucleophile in an in-line associative mechanism. The structure also suggests a catalytic role for Asp 129 in the reaction cycle.

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关键词：

Animals Cattle Cysteine Aspartic Acid Crystallography Protein Structure, Secondary Binding Sites Protein Tyrosine Phosphatases Catalysis Hydrogen Bonding