Summary: SNO glutamine amidotransferase family
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SNO glutamine amidotransferase family Provide feedback
This family and its amidotransferase domain was first described in . It is predicted that members of this family are involved in the pyridoxine biosynthetic pathway, based on the proximity and co-regulation of the corresponding genes and physical interaction between the members of PF01174 and PF01680 .
Galperin MY, Koonin EV; , Mol Microbiol 1997;24:443-445.: Sequence analysis of an exceptionally conserved operon suggests enzymes for a new link between histidine and purine biosynthesis. PUBMED:9159529 EPMC:9159529
Padilla PA, Fuge EK, Crawford ME, Errett A, Werner-Washburne M; , J Bacteriol 1998;180:5718-5726.: The highly conserved, coregulated SNO and SNZ gene families in Saccharomyces cerevisiae respond to nutrient limitation. PUBMED:9791124 EPMC:9791124
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR002161
This entry represents a family of pyridoxal 5'-phosphate synthase subunit, also known as the pdxT/SNO family. This family belongs to a superfamily containing a triad glutamine aminotransferase fold, characterised by a conserved Cys-His-Glu active site [PUBMED:14585832]. Two regions are highly conserved across all taxa, the PGGEST motif and the FHPE(LT) motif [PUBMED:11344146]. PdxT/SNO proteins are an alpha/beta three-layer sandwich containing a seven- stranded twisted mixed parallel beta-sheet flanked by a six alpha-helices on the N-terminal stretch of the sheet, four on one side and two on the other [PUBMED:14585832]. They are involved in vitamin B6 biosynthesis.
Proteins belonging to the pdxT/SNO family include:
- Bacillus subtilis glutamine amidotransferase subunit pdxT
- Haemophilus influenzae glutamine amidotransferase subunit pdxT
- Methanococcus jannaschii glutamine amidotransferase subunit pdxT
- Yeast probable glutamine amidotransferase SNO1
- Yeast probable glutamine amidotransferase SNO2
- Yeast probable glutamine amidotransferase SNO3
These are hydrophilic proteins of about 19 to 25 Kd.
The term vitamin B6 is used to refer collectively to the compound pyridoxine and its vitameric forms, pyridoxal, pyridoxamine, and their phosphorylated derivatives. Vitamin B6 is required by all organisms and plays an essential role as a co-factor for enzymatic reactions. Plants, fungi, bacteria, archaebacteria, and protists synthetize vitamin B6. Animals and some highly specialised obligate pathogens obtain it nutritionally. Vitamin B6 has two distinct biosynthetic pathways, which do not coexist in any organism. The pdxA/pdxJ pathway, that has been extensively characterised in Escherichia coli, is found in the gamma subdivision of the proteobacteria. A second pathway of vitamin B6 synthesis involving the pdxS/SNZ and pdxT/SNO protein families, which are completely unrelated in sequence to the pdxA/pdxJ proteins, is found in plants, fungi, protists, archaebacteria, and most bacteria.
PdxS/SNZ and pdxT/SNO proteins form a complex which serves as a glutamine amidotransferase to supply ammonia as a source of the ring nitrogen of vitamin B6 [PUBMED:14764090]. PdxT/SNO and pdxS/SNZ appear to encode respectively the glutaminase subunit, which produces ammonia from glutamine, and the synthase subunit, which combines ammonia with five- and three-carbon phosphosugars to form vitamin B6 [PUBMED:14762015].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||glutaminase activity (GO:0004359)|
|Biological process||vitamin B6 biosynthetic process (GO:0042819)|
|pyridoxal phosphate biosynthetic process (GO:0042823)|
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Most members of this clan are glutaminase enzymes. This superfamily is shown to be related in . The clan also contains the DJ-1/PfpI family that includes the peptidase PfpI that has a catalytic Cys-His-Glu triad that differs from the class I GAT Cys-His-Glu triad.
The clan contains the following 14 members:BPL_N DJ-1_PfpI DUF4159 GATase GATase1_like GATase_3 GATase_5 Glyco_hydro_42M HTS Peptidase_C26 Peptidase_S51 SNO ThiJ_like ThuA
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Curation and family details
|Author:||Belitsky B, Finn RD, Bateman A|
|Number in seed:||4|
|Number in full:||958|
|Average length of the domain:||176.80 aa|
|Average identity of full alignment:||39 %|
|Average coverage of the sequence by the domain:||91.58 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 11927849 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||16|
|Download:||download the raw HMM for this family|
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There are 2 interactions for this family. More...
We determine these interactions using iPfam, which considers the interactions between residues in three-dimensional protein structures and maps those interactions back to Pfam families. You can find more information about the iPfam algorithm in the journal article that accompanies the website.
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 SNO 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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