Summary: Carbohydrate phosphorylase
The Pfam group coordinates the annotation of Pfam families in Wikipedia, but we have not yet assigned a Wikipedia article to this family. If you think that a particular Wikipedia article provides good annotation, please let us know.
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.
Carbohydrate phosphorylase Provide feedback
The members of this family catalyse the formation of glucose 1-phosphate from one of the following polyglucoses; glycogen, starch, glucan or maltodextrin.
Leonidas DD, Oikonomakos NG, Papageorgiou AC, Acharya KR, Barford D, Johnson LN; , Protein Sci 1992;1:1112-1122.: Control of phosphorylase b conformation by a modified cofactor: crystallographic studies on R-state glycogen phosphorylase reconstituted with pyridoxal 5'-diphosphate. PUBMED:1304390 EPMC:1304390
Internal database links
|SCOOP:||Capsule_synth COX_ARM DUF3654|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR000811
The biosynthesis of disaccharides, oligosaccharides and polysaccharides involves the action of hundreds of different glycosyltransferases. These enzymes catalyse the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. A classification of glycosyltransferases using nucleotide diphospho-sugar, nucleotide monophospho-sugar and sugar phosphates (EC) and related proteins into distinct sequence based families has been described [PUBMED:9334165]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site. The same three-dimensional fold is expected to occur within each of the families. Because 3-D structures are better conserved than sequences, several of the families defined on the basis of sequence similarities may have similar 3-D structures and therefore form 'clans'.
The main role of glycogen phosphorylase (GPase) is to provide phosphorylated glucose molecules (G-1-P) [PUBMED:2182117]. GPase is a highly regulated allosteric enzyme. The net effect of the regulatory site allows the enzyme to operate at a variety of rates; the enzyme is not simply regulated as "on" or "off", but rather it can be thought of being set to operate at an ideal rate based on changing conditions at in the cell. The most important allosteric effector is the phosphate molecule covalently attached to Ser14. This switches GPase from the b (inactive) state to the a (active) state. Upon phosphorylation, GPase attains about 80% of its Vmax. When the enzyme is not phosphorylated, GPase activity is practically non-existent at low AMP levels.
There is some apparent controversy as to the structure of GPase. All sources agree that the enzyme is multimeric, but there is apparent controversy as to the enzyme being a tetramer or a dimer. Apparently, GPase (in the a form) forms tetramers in the crystal form. The consensus seems to be that `regardless of the a or b form, GPase functions as a dimer in vivo [PUBMED:2667896]. The GPase monomer is best described as consisting of two domains, an N-terminal domain and a C-terminal domain [PUBMED:8798388]. The C-terminal domain is often referred to as the catalytic domain. It consists of a beta-sheet core surrounded by layers of helical segments [PUBMED:2667896]. The vitamin cofactor pyridoxal phosphate (PLP) is covalently attached to the amino acid backbone. The N-terminal domain also consists of a central beta-sheet core and is surrounded by layers of helical segments. The N-terminal domain contains different allosteric effector sites to regulate the enzyme.
Bacterial phosphorylases follow the same catalytic mechanisms as their plant and animal counterparts, but differ considerably in terms of their substrate specificity and regulation. The catalytic domains are highly conserved while the regulatory sites are only poorly conserved. For maltodextrin phosphorylase from Escherichia coli the physiological role of the enzyme in the utilisation of maltidextrins is known in detail; that of all the other bacterial phosphorylases is still unclear. Roles in regulatuon of endogenous glycogen metabolism in periods of starvation, and sporulation, stress response or quick adaptation to changing environments are possible [PUBMED:10077830].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||glycogen phosphorylase activity (GO:0008184)|
|Biological process||carbohydrate metabolic process (GO:0005975)|
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- the UniProt description of the protein sequence
- the number of residues in the sequence
- the Pfam graphic itself.
Loading domain graphics...
This is the GT-B clan that contains diverse glycosyltransferases that possess a Rossmann like fold .
The clan contains the following 38 members:ALG11_N Alg14 Asp1 Capsule_synth DUF1205 DUF1972 DUF3492 DUF354 Epimerase_2 Glyco_tran_28_C Glyco_trans_1_2 Glyco_trans_1_3 Glyco_trans_1_4 Glyco_trans_4_2 Glyco_trans_4_3 Glyco_trans_4_4 Glyco_trans_4_5 Glyco_transf_20 Glyco_transf_28 Glyco_transf_4 Glyco_transf_41 Glyco_transf_5 Glyco_transf_56 Glyco_transf_9 Glyco_transf_90 Glycogen_syn Glycos_transf_1 Glycos_transf_N Glyphos_transf LpxB MGDG_synth Mito_fiss_Elm1 Phosphorylase PIGA PS_pyruv_trans SUA5 Sucrose_synth UDPGT
We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
- the alignment generated by searching the sequence database using the HMM
- Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
- alignment generated by searching the UniProtKB sequence database using the family HMM
- alignment generated by searching the NCBI sequence database using the family HMM
- alignment generated by searching the metagenomics sequence database using the family HMM
You can see the alignments as HTML or in three different sequence viewers:
1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
Format an alignment
If you find these logos useful in your own work, please consider citing the following article:
Note: You can also download the data file for the tree.
Curation and family details
|Number in seed:||601|
|Number in full:||3740|
|Average length of the domain:||492.60 aa|
|Average identity of full alignment:||32 %|
|Average coverage of the sequence by the domain:||75.64 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 17690987 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||18|
|Download:||download the raw HMM for this family|
Weight segments by...
Change the size of the sunburst
selected sequences to HMM
a FASTA-format file
- 0 sequences
- 0 species
How the sunburst is generated
Colouring and labels
Anomalies in the taxonomy tree
Missing taxonomic levels
Unmapped species names
Too many species/sequences
The tree shows the occurrence of this domain across different species. More...
You can use the tree controls to manipulate how the interactive tree is displayed:
- show/hide the summary boxes
- highlight species that are represented in the seed alignment
- expand/collapse the tree or expand it to a given depth
- select a sub-tree or a set of species within the tree and view them graphically or as an alignment
- save a plain text representation of the tree
There is 1 interaction 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 Phosphorylase domain has been found. There are 285 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.
Loading structure mapping...