Myo-inositol-1 -phosphate synthase

The General myo-lnositol and scyllo-Inosamine Pathway. Two distinct cyclitol pathways, which we earlier called Ca (started by myo-inositolphos-phate synthase) and Cb (started by T-deoxy-i cy/to-inosose synthase), are used in the initiation of AGA pathways. Here we will describe the Ca route and the Cb pathway in the paragraph on NEOs (see Section 2.2.2.1.3). The cyclitol pathway in the biosynthetic pathways for STRs, but also for other AGAs such as SPCs, KAS, and FORs and also the mixed type antibiotic HYG-A (see Section 2.2.4.3.1), starts with the formation of myo-inositol in a two-step pathway (Ca) that is not encoded in the itrAtt-clusters. The first step in streptidine biosynthesis (and any other myo-inositol utilising pathway) is the formation of a myo-inositol monophosphate (D-myo-inositol-3-phosphate or L-myo-inositol-1-phosphate) via L-myo-inositol-1-phosphate synthase, which in actinomycetes... 

Formation of the Initial Cyclitol. The first steps of FOR production are the same as in the biosynthesis of STR in short, the first step in FOR biosynthesis is postulated to be the formation of a myo-inositol monophosphate (D-myo-inositol-3-phosphate or L-myo-inositol-1-phosphate) via the cellular l-myo-inositol-1-phosphate synthase as in the STR pathway (Ca pathway see Section 2.2.1.2). As in the itr-Att-clusters, no gene for this enzyme has been found in the/or-cluster. As a second step in FOR biosynthesis the dephosphorylation of D-myo-inositol-3-phosphate via an inositolmonophosphate phosphatase has to follow. A putative gene product with this activity is that of the ForA protein (cf. Tables 2.17 and 2.18). The cyclitol is postulated to be first converted via two enzymes, a cluster-encoded myo-inositol 3-dehydrogenase (ForG member of the GFO/IDH/MocA oxidoreductase family) and the L-glutamine icy//o-3-inosose 3-aminotransferase (ketocyclitol aminotransferase I ForS), to icy//o-inosamine (3-deoxy-3-amino- cy/to-mositol). 

Loewus, M.W., Sasaki, K., Laevitt, A.L., Munsell, L., Sherman, W.R., and Loewus, F.A., 1982, The enantiomeric form of myo-inositol-1-phosphate produced by myo-inositol 1-phosphate synthase and myo-inositol kinase in higher plants. Plant Physiol. 70 1661-1663. 

Benaroya, R.O., Zamski, E., and Tel-Or, E., 2004, L-myo-inositol 1-phosphate synthase in the aquatic fern Azolla filiculoides. Plant Physiol. Biochem. 42 97-102. 

Majumder, A.L., Chatterjee, A., Dastidar, K.G., and Majee, M., 2003, Diversification and evolution of L-myo-inositol 1-phosphate synthase. FEBS Lett. 553 3-10. 

Sherman, W.R., Loewus, M.W., Pina, M.Z., and Wong, Y.-H.H., 1981, Studies on myo-inositol-1-phosphate synthase from Lilium longiflorum pollen, Neurospora crassa and bovine testis. Further evidence that a classical aldolase is not utilized. Biochim. Biophys. Acta 660 299-305. 

Yoshida, K.T., Wada, T., Koyama, H., Mizobuchi-Fukuoka, R., and Naito, S., 1999, Temporal and spatial patterns of accumulation of the transcript of myo-inositol 1-phosphate synthase and phytin-containing particles during seed development in rice. Plant Physiol. 119 65-72. 

Dean-Johnson, M., and Henry, S.A., 1989, Biosynthesis of inositol in yeast. Primary structure of myo-inositol-1-phosphate synthase (EC 5.5.1.4) and functional analysis of its structural gene, the inol locus. J. Biol. Chem. 264 1274-1283. 

Guan, G., Dai, P., and Shechter, I., 2003, cDNA cloning and gene expression analysis of human myo-inositol 1-phosphate synthase. Arch. Biochem. Biophys. 417 251-259. 

Jin, X., Foley, K.M., and Geiger, J.H., 2004, The structure of the lL-myo-inositol-1-phosphate synthase-NAD2+-deoxy-D-glucitol 6-(e)-vinylhomophosphonate complex demands a revision of the enzyme mechanism. J. Biol. Chem. 279 13889-13895. 

Maeda, T., and Eisenberg, F., Jr., 1980, Purification, structure, and catalytic properties of 1-myo-inositol-1 -phosphate synthase from rat testis. J. Biol. Chem. 255 8458-8464. 

Majee, M., Maitra, S., Ghosh Dastidar, K., Pattnaik, S., Chatterjee, A., Hait, N.C., Das, K.P., and Majumder, A.L., 2004, A novel salt-tolerant L-myo-inositol 1-phosphate synthase from Porteresia coarctata (Roxb.)Tateoka, a halophytic wild rice. Molecular cloning, bacterial overexpression, characterization and functional introgression into tobacco conferring salt-tolerance phenotype. J. Biol. Chem. 279 28539-28552. 

Wong, Y.H., Mauck, L.A., and Sherman, W.R., 1982, i,-myo-inositol-1 -phosphate synthase from bovine testis. Methods Enzymol. 90(Pt E) 309-314. 

Larson, S.R., and Raboy, V, 1999, Linkage mapping of maize and barley myo-inositol 1 -phosphate synthase DNA sequences Correspondence with a low phytic acid mutation. Theor. Appl. Genet. 99 27-36. 

Majumder, A.L., Johnson, M.D., and Henry, S.A., 1997, lL-myo-inositol-1 -phosphate synthase. Biochim. Biophys. Acta 1348 245-256. 

This enzyme was formerly known as myo-inositol-1-phosphate synthase. The recommendation for preferred nomenclature recently changed. Please refer to the website of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology at http // www. chem.qmul. ac. uk/iubmb/enzyme/. 

Pittner, F., Tovorova, J.J., Karnitskaya, E.Y., Khoklov, A.S., and Hoflfmann-Ostenhof, O., 1979, Myo-inositol 1-phosphate synthase from Streptomyces griseus (studies on the biosynthesis of cyclitols, XXXVIII). Mol. Cell. Biochem. 25 43. 

Keywords Inositol biosynthesis, lL-myo-inositol 1-phosphate synthase, D-glucose 6-phosphate, enzyme structure, enzyme mechanism. 

Byun, S.M., and Jenness, R., 1981, Stereospecificity of L-myo-inositol-1-phosphate synthase for nicotinamide adenine dinucleotide. Biochemistry 20 5174-5177. 

Jin, X.S., and Geiger, J.H., 2003, Structures of NAD(+)- and NADH-bound 1-L-myo-inositol 1-phosphate synthase. Acta Crystallogr Section o-Biol. Crystallogr. 59 1154—1164. 

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