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36  structures 916  species 2  interactions 1141  sequences 11  architectures

Family: Inos-1-P_synth (PF01658)

Summary: Myo-inositol-1-phosphate synthase

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This is the Wikipedia entry entitled "Inositol-3-phosphate synthase". More...

Inositol-3-phosphate synthase Edit Wikipedia article

inositol-3-phosphate synthase
Identifiers
EC number 5.5.1.4
CAS number 9032-95-5
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO
Myo-inositol-1-phosphate synthase
PDB 1u1i EBI.jpg
myo-inositol phosphate synthase mips from a. fulgidus
Identifiers
Symbol Inos-1-P_synth
Pfam PF01658
InterPro IPR013021
SCOP 1gr0
SUPERFAMILY 1gr0

In enzymology, an inositol-3-phosphate synthase (EC 5.5.1.4) is an enzyme that catalyzes the chemical reaction

D-glucose 6-phosphate \rightleftharpoons 1D-myo-inositol 3-phosphate

Hence, this enzyme has one substrate, D-glucose 6-phosphate, and one product, 1D-myo-inositol 3-phosphate.

This enzyme belongs to the family of isomerases, specifically the class of intramolecular lyases. The systematic name of this enzyme class is 1D-myo-inositol-3-phosphate lyase (isomerizing). Other names in common use include myo-inositol-1-phosphate synthase, D-glucose 6-phosphate cycloaldolase, inositol 1-phosphate synthatase, glucose 6-phosphate cyclase, inositol 1-phosphate synthetase, glucose-6-phosphate inositol monophosphate cycloaldolase, glucocycloaldolase, and 1L-myo-inositol-1-phosphate lyase (isomerizing).

This enzyme participates in streptomycin biosynthesis and inositol phosphate metabolism. It employs one cofactor, NAD+. The reaction this enzyme catalyses represents the first committed step in the production of all inositol-containing compounds, including phospholipids, either directly or by salvage. The enzyme exists in a cytoplasmic form in a wide range of plants, animals, and fungi. It has also been detected in several bacteria and a chloroplast form is observed in alga and higher plants. Inositol phosphates play an important role in signal transduction.

In Saccharomyces cerevisiae (Baker's yeast), the transcriptional regulation of the INO1 gene encoding inositol-3-phosphate synthase has been studied in detail and its expression is sensitive to the availability of phospholipid precursors as well as growth phase.[1] The regulation of the structural gene encoding 1L-myo-inositol-1-phosphate synthase has also been analyzed at the transcriptional level in the aquatic angiosperm, Spirodela polyrrhiza (Giant duckweed) and the halophyte, Mesembryanthemum crystallinum (Common ice plant).[2]

Structural studies

As of late 2007, 12 structures have been solved for this class of enzymes, with PDB accession codes 1GR0, 1JKF, 1JKI, 1LA2, 1P1F, 1P1H, 1P1I, 1P1J, 1P1K, 1RM0, 1VJP, and 1VKO.

References

  1. ^ Klig LS, Zobel PA, Devry CG, Losberger C (June 1994). "Comparison of INO1 gene sequences and products in Candida albicans and Saccharomyces cerevisiae". Yeast 10 (6): 789–800. doi:10.1002/yea.320100609. PMID 7975896. 
  2. ^ Majumder AL, Johnson MD, Henry SA (September 1997). "1L-myo-inositol-1-phosphate synthase". Biochim. Biophys. Acta 1348 (1-2): 245–56. doi:10.1016/s0005-2760(97)00122-7. PMID 9370339. 

Further reading

This article incorporates text from the public domain Pfam and InterPro IPR013021

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Myo-inositol-1-phosphate synthase Provide feedback

This is a family of myo-inositol-1-phosphate synthases. Inositol-1-phosphate catalyses the conversion of glucose-6- phosphate to inositol-1-phosphate, which is then dephosphorylated to inositol [1]. Inositol phosphates play an important role in signal transduction.

Literature references

  1. Klig LS, Zobel PA, Devry CG, Losberger C; , Yeast 1994;10:789-800.: Comparison of INO1 gene sequences and products in Candida albicans and Saccharomyces cerevisiae. PUBMED:7975896 EPMC:7975896


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR013021

This is a region of myo-inositol-1-phosphate synthases that is related to the glyceraldehyde-3-phosphate dehydrogenase-like, C-terminal domain.

1L-myo-Inositol-1-phosphate synthase (EC) catalyzes the conversion of D-glucose 6-phosphate to 1L-myo-inositol-1-phosphate, the first committed step in the production of all inositol-containing compounds, including phospholipids, either directly or by salvage. The enzyme exists in a cytoplasmic form in a wide range of plants, animals, and fungi. It has also been detected in several bacteria and a chloroplast form is observed in alga and higher plants. Inositol phosphates play an important role in signal transduction.

In Saccharomyces cerevisiae (Baker's yeast), the transcriptional regulation of the INO1 gene has been studied in detail [PUBMED:7975896] and its expression is sensitive to the availability of phospholipid precursors as well as growth phase. The regulation of the structural gene encoding 1L-myo-inositol-1-phosphate synthase has also been analyzed at the transcriptional level in the aquatic angiosperm, Spirodela polyrrhiza (Giant duckweed) and the halophyte, Mesembryanthemum crystallinum (Common ice plant) [PUBMED:9370339].

Domain organisation

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Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

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(1086)
Meta
(280)
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(186)
RP35
(341)
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RP75
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  Seed
(60)
Full
(1141)
Representative proteomes NCBI
(1086)
Meta
(280)
RP15
(186)
RP35
(341)
RP55
(459)
RP75
(533)
Alignment:
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  Seed
(60)
Full
(1141)
Representative proteomes NCBI
(1086)
Meta
(280)
RP15
(186)
RP35
(341)
RP55
(459)
RP75
(533)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

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Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Pfam-B_959 (release 4.1)
Previous IDs: none
Type: Family
Author: Bashton M, Bateman A
Number in seed: 60
Number in full: 1141
Average length of the domain: 110.30 aa
Average identity of full alignment: 40 %
Average coverage of the sequence by the domain: 26.16 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 20.0 20.0
Trusted cut-off 20.0 24.6
Noise cut-off 19.3 18.5
Model length: 112
Family (HMM) version: 12
Download: download the raw HMM for this family

Species distribution

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Interactions

There are 2 interactions for this family. More...

NAD_binding_5 Inos-1-P_synth

Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Inos-1-P_synth domain has been found. There are 36 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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