Unknown

Dataset Information

0

Structural and biochemical characterization of Siw14: A protein-tyrosine phosphatase fold that metabolizes inositol pyrophosphates.


ABSTRACT: Inositol pyrophosphates (PP-InsPs) are "energetic" intracellular signals that are ubiquitous in animals, plants, and fungi; structural and biochemical characterization of PP-InsP metabolic enzymes provides insight into their evolution, reaction mechanisms, and regulation. Here, we describe the 2.35-Å-resolution structure of the catalytic core of Siw14, a 5-PP-InsP phosphatase from Saccharomyces cerevisiae and a member of the protein tyrosine-phosphatase (PTP) superfamily. Conclusions that we derive from structural data are supported by extensive site-directed mutagenesis and kinetic analyses, thereby attributing new functional significance to several key residues. We demonstrate the high activity and exquisite specificity of Siw14 for the 5-diphosphate group of PP-InsPs. The three structural elements that demarcate a 9.2-Å-deep substrate-binding pocket each have spatial equivalents in PTPs, but we identify how these are specialized for Siw14 to bind and hydrolyze the intensely negatively charged PP-InsPs. (a) The catalytic P-loop with the CX5R(S/T) PTP motif contains additional, positively charged residues. (b) A loop between the ?5 and ?6 helices, corresponding to the Q-loop in PTPs, contains a lysine and an arginine that extend into the catalytic pocket due to displacement of the ?5 helix orientation through intramolecular crowding caused by three bulky, hydrophobic residues. (c) The general-acid loop in PTPs is replaced in Siw14 with a flexible loop that does not use an aspartate or glutamate as a general acid. We propose that an acidic residue is not required for phosphoanhydride hydrolysis.

SUBMITTER: Wang H 

PROVIDER: S-EPMC5936820 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

altmetric image

Publications

Structural and biochemical characterization of Siw14: A protein-tyrosine phosphatase fold that metabolizes inositol pyrophosphates.

Wang Huanchen H   Gu Chunfang C   Rolfes Ronda J RJ   Jessen Henning J HJ   Shears Stephen B SB  

The Journal of biological chemistry 20180314 18


Inositol pyrophosphates (PP-InsPs) are "energetic" intracellular signals that are ubiquitous in animals, plants, and fungi; structural and biochemical characterization of PP-InsP metabolic enzymes provides insight into their evolution, reaction mechanisms, and regulation. Here, we describe the 2.35-Å-resolution structure of the catalytic core of Siw14, a 5-PP-InsP phosphatase from <i>Saccharomyces cerevisiae</i> and a member of the protein tyrosine-phosphatase (PTP) superfamily. Conclusions that  ...[more]

Similar Datasets

| S-EPMC2206706 | biostudies-literature
| S-EPMC3323020 | biostudies-literature
| S-EPMC4897736 | biostudies-literature
| S-EPMC2000531 | biostudies-literature
| S-EPMC137862 | biostudies-literature
| S-EPMC3981807 | biostudies-literature
| S-EPMC3946838 | biostudies-literature
| S-EPMC3839729 | biostudies-literature
| S-EPMC2667744 | biostudies-literature
| S-EPMC3308798 | biostudies-literature