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Inositol Monophosphatase (1DK4)

is a homodimeric phosphatase. This protein structure is derived from the the methanogen Methanococcus jannaschii gene MJ0109. Curiously this protein shows both Inositol Monophosphate (IMPase) activity as well as Fructose 1,6 Bisphosphatase acivity (FBPase)^[1]. This protein has a homolog in another archeabacteria, Archaeoglobus fulgidus^[2]. It is thought to be a precursor of many phophatases in higher organisms^[3]. Template:STRUCTURE 1dk4

Contents 1 Inositol Monophosphatase (1DK4) 2 Methanococcus jannaschii[1] 3 Structure 4 Function 4.1 bipolar disorder 5 References

Methanococcus jannaschii[1]

M. jannaschii are thermophilc methane producing archeabacteria that were discovered in 1983 the manned submersible ALVIN[2]. They were sampled from the base of a deep sea hydrothermal vent in 2600m of water, local tempurature was 85°C. The complete 1.66 mega base pairs of its genome has been sequenced, about 1738 genes were identified, most of them were determined to be homologous to eukaryotic proteins^[4].

Structure

The general structure of this enzyme is a homodimer, composed of 253 amino acid residues. IMPase falls within the metallo-phosphatase family^[5]. This particular structure has been crystalized in complex with a (red and orange), and three inhibitory Zn^2+ ions (grey) per subunit. Each subunit is composed of 5 layers alternating helix, sheet, helix, sheet, then helix. Additionally, each subunit possess its own large hydrophilic active site.

Function

IMPase activity within M. jannaschii is mainly limited to the production of a unique inositol, di-myo-inositol-1,1'-phosphate (DIP). Intracellular DIP concentrations increase usually in response to supraoptimal growth temperatures, and is involved in maintaining high cellular concentration of K+ which sustains optimal enzyme activity^[6].

bipolar disorder

descibe the disorder, and Li+ inhibition FBPase gluconeogenesis, fructose 1,6 bisphosphate to fructose 6 phosphate.

References

1. ↑ Stec B, Yang H, Johnson KA, Chen L, Roberts MF. MJ0109 is an enzyme that is both an inositol monophosphatase and the 'missing' archaeal fructose-1,6-bisphosphatase. Nat Struct Biol. 2000 Nov;7(11):1046-50. PMID:11062561 doi:10.1038/80968
2. ↑ Stieglitz KA, Johnson KA, Yang H, Roberts MF, Seaton BA, Head JF, Stec B. Crystal structure of a dual activity IMPase/FBPase (AF2372) from Archaeoglobus fulgidus. The story of a mobile loop. J Biol Chem. 2002 Jun 21;277(25):22863-74. Epub 2002 Apr 8. PMID:11940584 doi:http://dx.doi.org/10.1074/jbc.M201042200
3. ↑ Stec B, Yang H, Johnson KA, Chen L, Roberts MF. MJ0109 is an enzyme that is both an inositol monophosphatase and the 'missing' archaeal fructose-1,6-bisphosphatase. Nat Struct Biol. 2000 Nov;7(11):1046-50. PMID:11062561 doi:10.1038/80968
4. ↑ Bult CJ, White O, Olsen GJ, Zhou L, Fleischmann RD, Sutton GG, Blake JA, FitzGerald LM, Clayton RA, Gocayne JD, Kerlavage AR, Dougherty BA, Tomb JF, Adams MD, Reich CI, Overbeek R, Kirkness EF, Weinstock KG, Merrick JM, Glodek A, Scott JL, Geoghagen NS, Venter JC. Complete genome sequence of the methanogenic archaeon, Methanococcus jannaschii. Science. 1996 Aug 23;273(5278):1058-73. PMID:8688087
5. ↑ Stec B, Yang H, Johnson KA, Chen L, Roberts MF. MJ0109 is an enzyme that is both an inositol monophosphatase and the 'missing' archaeal fructose-1,6-bisphosphatase. Nat Struct Biol. 2000 Nov;7(11):1046-50. PMID:11062561 doi:10.1038/80968
6. ↑ Chen L, Spiliotis ET, Roberts MF. Biosynthesis of Di-myo-inositol-1,1'-phosphate, a novel osmolyte in hyperthermophilic archaea. J Bacteriol. 1998 Aug;180(15):3785-92. PMID:9683472