Crystal structure of Staphylococcal dual specific inositol monophosphatase/NADP(H) phosphatase (SAS2203) delineates the molecular basis of substrate specificity

Bhattacharyya, Sudipta; Dutta, Debajyoti; Saha, Barun Kumar; Ghosh, Ananta K.; Das, Amit Kumar

doi:10.1016/j.biochi.2011.12.007

Cited by 13 publications

(30 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, in the absence of an inhibitory excess of MgCl 2 , Mg 2+ replacement was observed in the 50 m m LiCl‐soaked structure (batch C crystals). Therefore, the soaking experiments showed complete agreement with the results of the biochemical study, such as an IC 50 value of Li + in SaIMPase I (53 m m ) and the mutually exclusive nature of Mg 2+ and Li + binding. No dissociation of Mg 2+ was observed when the crystals were soaked for 24 h in a reservoir solution lacking both Mg 2+ and Li + (batch A) (Table ).…”

Section: Resultssupporting

confidence: 80%

“…Biochemical experiments suggested that Li + acts as a competitive inhibitor of the cofactor Mg 2+ . Moreover, at low concentrations, Li + acts as an uncompetitive inhibitor with respect to the substrate . The Mg 2+ ‐induced inhibition pattern resembles that exerted by Li + at low concentrations.…”

Section: Resultsmentioning

confidence: 96%

“…First, the mechanism cannot explain the 'burst phase' release of inositol during Li + inhibition [21]. Second, it does not explain the linear non-competitive mode of Li + inhibition at higher Li + concentrations [21,22]. The non-competitive mode indicates that Li + is able to bind the free enzyme (low-affinity binding site) and the enzyme-substrate or enzymeproduct complex (high-affinity binding site).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structural elucidation of the binding site and mode of inhibition of Li⁺ and Mg²⁺ in inositol monophosphatase

et al. 2014

Self Cite

View full text Add to dashboard Cite

Mg2+‐dependent, Li+‐sensitive phosphatases are a widely distributed family of enzymes with significant importance throughout the biological kingdom. Inositol monophosphatase (IMPase) is an important target of Li+‐based therapeutic agents in manic depressive disorders. However, despite decades of intense research efforts, the precise mechanism of Li+‐induced inhibition of IMPase remains obscured. Here we describe a structural investigation of the Li+ binding site in staphylococcal IMPase I (SaIMPase I) using X–ray crystallography. The biochemical study indicated common or overlapping binding sites for Mg2+ and Li+ in the active site of SaIMPase I. The crystal structure of the SaIMPase I ternary product complex shows the presence of a phosphate and three Mg2+ ions (namely Mg1, Mg2 and Mg3) in the active site. As Li+ is virtually invisible in X–ray crystallography, competitive displacement of Mg2+ ions from the SaIMPase I ternary product complex as a function of increasing LiCl concentration was used to identify the Li+ binding site. In this approach, the disappearing electron density of Mg2+ ions due to Li+ ion binding was traced, and the Mg2+ ion present at the Mg2 binding site was found to be replaced. Moreover, based on a detailed comparative investigation of the phosphate orientation and coordination states of Mg2+ binding sites in enzyme–substrate and enzyme–product complexes, inhibition mechanisms for Li+ and Mg2+ are proposed. Database The atomic coordinates for the SaIMPase I ternary complex, SaIMPase I in 50 mm LiCl, SaIMPase I in 100 mm LiCl and SaIMPase I in 0 mm MgCl2 have been submitted to the Protein Data Bank under accession numbers http://www.rcsb.org/pdb/search/structidSearch.do?structureId=4G61, http://www.rcsb.org/pdb/search/structidSearch.do?structureId=4I40, http://www.rcsb.org/pdb/search/structidSearch.do?structureId=4I3Y and http://www.rcsb.org/pdb/search/structidSearch.do?structureId=4PTK, respectively. Structured digital abstract SaIMPase-I and SaIMPase-I bind by x-ray crystallography ( View interaction)

show abstract

Section: Resultssupporting

confidence: 80%

Section: Resultsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structural elucidation of the binding site and mode of inhibition of Li⁺ and Mg²⁺ in inositol monophosphatase

et al. 2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…For IMPase, three atoms of a divalent cation are associated with the active site. The preferential divalent cation is Mg 2+ [21, 55] although Mn 2+ [56, 57] or Ca 2+ [58] can substitute for Mg 2+ . Mg 2+ , which can bind with different affinities to each binding site in IMPase, is required for efficient substrate binding [59].…”

Section: Discussionmentioning

confidence: 99%

Direct Ionic Regulation of the Activity of Myo-Inositol Biosynthesis Enzymes in Mozambique Tilapia

Villarreal

Kültz

2015

PLoS ONE

View full text Add to dashboard Cite

Myo-inositol (Ins) is a major compatible osmolyte in many cells, including those of Mozambique tilapia (Oreochromis mossambicus). Ins biosynthesis is highly up-regulated in tilapia and other euryhaline fish exposed to hyperosmotic stress. In this study, enzymatic regulation of two enzymes of Ins biosynthesis, Ins phosphate synthase (MIPS) and inositol monophosphatase (IMPase), by direct ionic effects is analyzed. Specific MIPS and IMPase isoforms from Mozambique tilapia (MIPS-160 and IMPase 1) were selected based on experimental, phylogenetic, and structural evidence supporting their role for Ins biosynthesis during hyperosmotic stress. Recombinant tilapia IMPase 1 and MIPS-160 activity was assayed in vitro at ionic conditions that mimic changes in the intracellular milieu during hyperosmotic stress. The in vitro activities of MIPS-160 and IMPase 1 are highest at alkaline pH of 8.8. IMPase 1 catalytic efficiency is strongly increased during hyperosmolality (particularly for the substrate D-Ins-3-phosphate, Ins-3P), mainly as a result of [Na+] elevation. Furthermore, the substrate-specificity of IMPase 1 towards D-Ins-1-phosphate (Ins-1P) is lower than towards Ins-3P. Because MIPS catalysis results in Ins-3P this results represents additional evidence for IMPase 1 being the isoform that mediates Ins biosynthesis in tilapia. Our data collectively demonstrate that the Ins biosynthesis enzymes are activated under ionic conditions that cells are exposed to during hypertonicity, resulting in Ins accumulation, which, in turn, results in restoration of intracellular ion homeostasis. We propose that the unique and direct ionic regulation of the activities of Ins biosynthesis enzymes represents an efficient biochemical feedback loop for regulation of intracellular physiological ion homeostasis during hyperosmotic stress.

show abstract

“…For protein tyrosine phosphatases, the depth of the cleft matches the length of a phosphotyrosine residue, whereas the shorter phosphoserine/threonine residues are not able to reach the catalytic cysteine. In contrast, typical catalytic loop of dual-specific phosphatases are at the bottom of a much shallower pocket, which gives access to all three phosphorylated hydroxyl amino acids (Myers et al 1997;Bhattacharyya et al 2012). The amino-terminal domain of PTEN contains the signature motif HCKAGKGR for protein tyrosine phosphatases, forming the P-loop (residues H123-R130) at the bottom of its active site pocket with cysteine being at the bottom of the catalytic pocket (Lee et al 1999).…”

mentioning

confidence: 99%

Dual-Specific Protein and Lipid Phosphatase PTEN and Its Biological Functions

Chen

et al. 2019

Cold Spring Harb Perspect Med

View full text Add to dashboard Cite

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) encodes a 403-amino acid protein with an amino-terminal domain that shares sequence homology with the actinbinding protein tensin and the putative tyrosine-protein phosphatase auxilin. Crystal structure analysis of PTEN has revealed a C2 domain that binds to phospholipids in membranes and a phosphatase domain that displays dual-specific activity toward both tyrosine (Y), serine (S)/ threonine (T), as well as lipid substrates in vitro. Characterized primarily as a lipid phosphatase, PTEN plays important roles in multiple cellular processes including cell growth/survival as well as metabolism.

show abstract

Crystal structure of Staphylococcal dual specific inositol monophosphatase/NADP(H) phosphatase (SAS2203) delineates the molecular basis of substrate specificity

Cited by 13 publications

References 37 publications

Structural elucidation of the binding site and mode of inhibition of Li⁺ and Mg²⁺ in inositol monophosphatase

Structural elucidation of the binding site and mode of inhibition of Li⁺ and Mg²⁺ in inositol monophosphatase

Direct Ionic Regulation of the Activity of Myo-Inositol Biosynthesis Enzymes in Mozambique Tilapia

Dual-Specific Protein and Lipid Phosphatase PTEN and Its Biological Functions

Contact Info

Product

Resources

About

Crystal structure of Staphylococcal dual specific inositol monophosphatase/NADP(H) phosphatase (SAS2203) delineates the molecular basis of substrate specificity

Cited by 13 publications

References 37 publications

Structural elucidation of the binding site and mode of inhibition of Li+ and Mg2+ in inositol monophosphatase

Structural elucidation of the binding site and mode of inhibition of Li+ and Mg2+ in inositol monophosphatase

Direct Ionic Regulation of the Activity of Myo-Inositol Biosynthesis Enzymes in Mozambique Tilapia

Dual-Specific Protein and Lipid Phosphatase PTEN and Its Biological Functions

Contact Info

Product

Resources

About

Structural elucidation of the binding site and mode of inhibition of Li⁺ and Mg²⁺ in inositol monophosphatase

Structural elucidation of the binding site and mode of inhibition of Li⁺ and Mg²⁺ in inositol monophosphatase