Summary: Arginosuccinate synthase
Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.
This is the Wikipedia entry entitled "Argininosuccinate synthase". More...
The Wikipedia text that you see displayed here is a download from Wikipedia. This means that the information we display is a copy of the information from the Wikipedia database. The button next to the article title ("Edit Wikipedia article") takes you to the edit page for the article directly within Wikipedia. You should be aware you are not editing our local copy of this information. Any changes that you make to the Wikipedia article will not be displayed here until we next download the article from Wikipedia. We currently download new content on a nightly basis.
Does Pfam agree with the content of the Wikipedia entry ?
Pfam has chosen to link families to Wikipedia articles. In some case we have created or edited these articles but in many other cases we have not made any direct contribution to the content of the article. The Wikipedia community does monitor edits to try to ensure that (a) the quality of article annotation increases, and (b) vandalism is very quickly dealt with. However, we would like to emphasise that Pfam does not curate the Wikipedia entries and we cannot guarantee the accuracy of the information on the Wikipedia page.
Editing Wikipedia articles
Before you edit for the first time
Wikipedia is a free, online encyclopedia. Although anyone can edit or contribute to an article, Wikipedia has some strong editing guidelines and policies, which promote the Wikipedia standard of style and etiquette. Your edits and contributions are more likely to be accepted (and remain) if they are in accordance with this policy.
You should take a few minutes to view the following pages:
How your contribution will be recorded
Anyone can edit a Wikipedia entry. You can do this either as a new user or you can register with Wikipedia and log on. When you click on the "Edit Wikipedia article" button, your browser will direct you to the edit page for this entry in Wikipedia. If you are a registered user and currently logged in, your changes will be recorded under your Wikipedia user name. However, if you are not a registered user or are not logged on, your changes will be logged under your computer's IP address. This has two main implications. Firstly, as a registered Wikipedia user your edits are more likely seen as valuable contribution (although all edits are open to community scrutiny regardless). Secondly, if you edit under an IP address you may be sharing this IP address with other users. If your IP address has previously been blocked (due to being flagged as a source of 'vandalism') your edits will also be blocked. You can find more information on this and creating a user account at Wikipedia.
If you have problems editing a particular page, contact us at firstname.lastname@example.org and we will try to help.
The community annotation is a new facility of the Pfam web site. If you have problems editing or experience problems with these pages please contact us.
Argininosuccinate synthase Edit Wikipedia article
Crystallographic structure of human argininosuccinate synthetase.
|PDB structures||RCSB PDB PDBe PDBsum|
|Gene Ontology||AmiGO / EGO|
|Argininosuccinate synthetase 1|
|Locus||Chr. 9 q34.1|
crystal structure of thermus thermophilus hb8 argininosuccinate synthetase in complex with atp and citrulline
Genetic structure[edit sourceÂ | edit]
The gene that encodes for this enzyme, ASS, is located on chromosome 9. In humans, ASS is expressed mostly in the cells of liver and kidney. The expressed ASS gene is at least 65 kb in length, including at least 12 introns.
Enzyme mechanism[edit sourceÂ | edit]
In the first step of the catalyzed reaction, citrulline attacks the Î±-phosphate of ATP to form citrulline adenylate, a reactive intermediate. The attachment of AMP to the ureido (urea-like) group on citrulline activates the carbonyl center for subsequent nucleophilic attack. This activation facilitates the second step, in which the Î±-amino group of aspartate attacks the ureido group. Attack by aspartate is the rate-limiting step of the reaction. This step produces free AMP and L-argininosuccinate.
Thermodynamically, adenylation of the citrulline ureido group is more favorable than the analogous phosphorylation. Additionally, attack by citrulline at the Î±-phosphate of ATP produces an equivalent of pyrophosphate, which can be hydrolyzed in a thermodynamically favorable reaction to provide additional energy to drive the adenylation.
Enzyme structure[edit sourceÂ | edit]
Argininosuccinate synthetase is a homotetramer, with each subunit consisting of 412 residues. The interfaces between subunits contain a number of bridges and hydrogen bonds, and the C-terminus of each subunit is involved in oligomerization by interacting with the C-termini and nucleotide-binding domains of the other subunits.
X-ray crystal structures have been generated for argininosuccinate synthetase from Thermus thermophilus, E. coli, Thermotoga maritime, and Homo sapiens. In ASS from T. thermophilus, E. coli, and H. sapiens, citrulline and aspartate are tightly bound in the active site by interactions with serine and arginine residues; interactions of the substrates with other residues in the active site vary by species. In T. thermophilus, the ureido group of citrulline appears to be repositioned during nucleophilic attack to attain sufficient proximity to the Î±-phosphate of ATP. In E. coli, it is suggested that binding of ATP causes a conformational shift that brings together the nucleotide-binding domain and the synthetase domain. An argininosuccinate synthetase structure with a bound ATP in the active site has not been attained, although modeling suggests that the distance between ATP and the ureido group of citrulline is smaller in human argininosuccinate synthetase than in the E. coli variety, so it is likely that a much smaller conformational change is necessary for catalysis. The ATP binding domain of argininosuccinate synthetase is similar to that of other N-type ATP pyrophosphatases.
Biological function[edit sourceÂ | edit]
The transformation of citrulline into argininosuccinate is the rate-limiting step in arginine synthesis. The activity of argininosuccinate synthetase in arginine synthesis occurs largely in at the outer mitochondrial membrane of periportal liver cells as part of the urea cycle, with some activity occurring in cortical kidney cells. Genetic defects that cause incorrect localization of argininosuccinate synthetase to the outer mitochondrial membrane cause type II citrullinemia.
In fetuses and infants, arginine is also produced via argininosuccinate synthetase activity in intestinal cells, presumably to supplement the low level of arginine found in motherâs milk. Expression of argininosuccinate synthetase in the intestines ceases after two to three years of life.
It is thought that regulation of argininosuccinate synthetase activity in arginine synthesis occurs primarily at the transcriptional level in response to glucocorticoids, cAMP, glucagon, and insulin. It has also been demonstrated in vitro that arginine down-regulates argininosuccinate synthetase expression, while citrulline up-regulates it.
The enzyme endothelial nitric oxide synthase produces nitric oxide from arginine in endothelial cells. Argininosuccinate synthetase and argininosuccinate lyase recycle citrulline, a byproduct of nitric oxide production, into arginine. Since nitric oxide is an important signaling molecule, this role of ASS is important to vascular physiology. In this role, argininosuccinate synthetase activity is regulated largely by inflammatory cellular signal molecules such as cytokines.
In endothelial cells, it has been shown that ASS expression is increased by laminar shear stress due to pulsative blood flow. Emerging evidence suggests that ASS may also be subject to regulation by phosphorylation at the Ser-328 residue by protein kinase C-Î± and by nitrosylation at the Cys-132 residue by nitric oxide synthase.
Role in disease[edit sourceÂ | edit]
Citrullinemia is an inherited autosomal recessive disease. At least 50 mutations that cause type I citrullinemia have been identified in the ASS gene. Most of these mutations substitute one amino acid for another in ASS. These mutations likely affect the structure of the enzyme and its ability to bind to citrulline, aspartate, and other molecules. A few mutations lead to the production of an abnormally short enzyme that cannot effectively play its role in the urea cycle.
Defects in ASS disrupt the third step of the urea cycle, preventing the liver from processing excess nitrogen into urea. As a result, nitrogen (in the form of ammonia) and other byproducts of the urea cycle (such as citrulline) build up in the bloodstream. Ammonia is toxic, particularly to the nervous system. An accumulation of ammonia during the first few days of life leads to poor feeding, vomiting, seizures, and the other signs and symptoms of type I citrullinemia.
Treatment for this defect includes a low-protein diet and dietary supplementation with arginine and phenylacetate. Arginine allows the urea cycle to complete itself, creating the substrates needed to originally fix ammonia. This will lower blood pH. Additionally, phenylacetate reacts with backed-up glutamine, resulting on phenylacetoglutamine, which can be excreted renally.
A lack of argininosuccinate synthetase expression has been observed in several types of cancer cells, including pancreatic cancer, liver cancer, and melanoma. For example, defects in ASS have been seen in 87% of pancreatic cancers. Cancer cells are therefore unable to synthesis enough arginine for cellular processes and so must rely on dietary arginine. Depletion of plasma arginine using arginine deiminase has been shown to lead to regression of tumours in mice.
See also[edit sourceÂ | edit]
References[edit sourceÂ | edit]
- PDB 2nz2; Karlberg T, Collins R, van den Berg S, Flores A, HammarstrÃ¶m M, HÃ¶gbom M, Holmberg Schiavone L, Uppenberg J (March 2008). "Structure of human argininosuccinate synthetase". Acta Crystallogr. D Biol. Crystallogr. 64 (Pt 3): 279â86. doi:10.1107/S0907444907067455. PMID 18323623.
- Goto M, Omi R, Miyahara I, Sugahara M, Hirotsu K (June 2003). "Structures of argininosuccinate synthetase in enzyme-ATP substrates and enzyme-AMP product forms: stereochemistry of the catalytic reaction". J. Biol. Chem. 278 (25): 22964â71. doi:10.1074/jbc.M213198200. PMID 12684518.
- Freytag SO, Beaudet AL, Bock HG, O'Brien WE (October 1984). "Molecular structure of the human argininosuccinate synthetase gene: occurrence of alternative mRNA splicing". Mol. Cell. Biol. 4 (10): 1978â84. PMC 369014. PMID 6095035.
- Ghose C, Raushel FM (October 1985). "Determination of the mechanism of the argininosuccinate synthetase reaction by static and dynamic quench experiments". Biochemistry 24 (21): 5894â8. doi:10.1021/bi00342a031. PMID 3878725.
- Kumar S, Lennane J, Ratner S (October 1985). "Argininosuccinate synthetase: essential role of cysteine and arginine residues in relation to structure and mechanism of ATP activation". Proc. Natl. Acad. Sci. U.S.A. 82 (20): 6745â9. doi:10.1073/pnas.82.20.6745. PMC 390763. PMID 3863125.
- Husson A, Brasse-Lagnel C, Fairand A, Renouf S, Lavoinne A (May 2003). "Argininosuccinate synthetase from the urea cycle to the citrulline-NO cycle". Eur. J. Biochem. 270 (9): 1887â99. doi:10.1046/j.1432-1033.2003.03559.x. PMID 12709047.
- Karlberg T, Collins R, van den Berg S, Flores A, HammarstrÃ¶m M, HÃ¶gbom M, Holmberg Schiavone L, Uppenberg J (March 2008). "Structure of human argininosuccinate synthetase". Acta Crystallogr. D Biol. Crystallogr. 64 (Pt 3): 279â86. doi:10.1107/S0907444907067455. PMID 18323623.
- Lemke CT, Howell PL (December 2001). "The 1.6 A crystal structure of E. coli argininosuccinate synthetase suggests a conformational change during catalysis". Structure 9 (12): 1153â64. doi:10.1016/S0969-2126(01)00683-9. PMID 11738042.
- Haines RJ, Pendleton LC, Eichler DC (2011). "Argininosuccinate synthase: at the center of arginine metabolism". Int J Biochem Mol Biol 2 (1): 8â23. PMC 3074183. PMID 21494411.
- Morris SM (2002). "Regulation of enzymes of the urea cycle and arginine metabolism". Annu. Rev. Nutr. 22: 87â105. doi:10.1146/annurev.nutr.22.110801.140547. PMID 12055339.
- Mun GI, Boo YC (April 2012). "A regulatory role of Kruppel-like factor 4 in endothelial argininosuccinate synthetase 1 expression in response to laminar shear stress". Biochem. Biophys. Res. Commun. 420 (2): 450â5. doi:10.1016/j.bbrc.2012.03.016. PMID 22430140.
- Haines RJ, Corbin KD, Pendleton LC, Eichler DC (July 2012). "Protein kinase CÎ± phosphorylates a novel argininosuccinate synthase site at serine 328 during calcium-dependent stimulation of endothelial nitric-oxide synthase in vascular endothelial cells". J. Biol. Chem. 287 (31): 26168â76. doi:10.1074/jbc.M112.378794. PMC 3406701. PMID 22696221.
- HÃ¤berle J, Pauli S, Linnebank M, Kleijer WJ, Bakker HD, Wanders RJ, Harms E, Koch HG (April 2002). "Structure of the human argininosuccinate synthetase gene and an improved system for molecular diagnostics in patients with classical and mild citrullinemia". Hum. Genet. 110 (4): 327â33. doi:10.1007/s00439-002-0686-6. PMID 11941481.
- Devlin TM (2002). Textbook of biochemistry: with clinical correlations. New York: Wiley-Liss. p. 788. ISBN 0-471-41136-1.
- Wu L, Li L, Meng S, Qi R, Mao Z, Lin M (February 2013). "Expression of argininosuccinate synthetase in patients with hepatocellular carcinoma". J. Gastroenterol. Hepatol. 28 (2): 365â8. doi:10.1111/jgh.12043. PMID 23339388.
- Yoon JK, Frankel AE, Feun LG, Ekmekcioglu S, Kim KB (2013). "Arginine deprivation therapy for malignant melanoma". Clin Pharmacol 5: 11â9. doi:10.2147/CPAA.S37350. PMC 3534294. PMID 23293541.
- Bowles TL, Kim R, Galante J, Parsons CM, Virudachalam S, Kung HJ, Bold RJ (October 2008). "Pancreatic cancer cell lines deficient in argininosuccinate synthetase are sensitive to arginine deprivation by arginine deiminase". Int. J. Cancer 123 (8): 1950â5. doi:10.1002/ijc.23723. PMID 18661517.
[edit sourceÂ | edit]
- GeneReviews/NCBI/NIH/UW entry on Argininosuccinate Synthetase Deficiency; ASS Deficiency; Argininosuccinic Acid Synthetase Deficiency; CTLN1; Citrullinemia, Classic
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.
Arginosuccinate synthase Provide feedback
This family contains a PP-loop motif .
Bork P, Koonin EV; , Proteins 1994;20:347-355.: A P-loop-like motif in a widespread ATP pyrophosphatase domain: implications for the evolution of sequence motifs and enzyme activity. PUBMED:7731953 EPMC:7731953
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR001518
Argininosuccinate synthase (EC) (AS) is a urea cycle enzyme that catalyzes the penultimate step in arginine biosynthesis: the ATP-dependent ligation of citrulline to aspartate to form argininosuccinate, AMP and pyrophosphate [PUBMED:2123815, PUBMED:3133361].
In humans, a defect in the AS gene causes citrullinemia, a genetic disease characterised by severe vomiting spells and mental retardation.
AS is a homotetrameric enzyme of chains of about 400 amino-acid residues. An arginine seems to be important for the enzyme's catalytic mechanism. The sequences of AS from various prokaryotes, archaebacteria and eukaryotes show significant similarity.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||ATP binding (GO:0005524)|
|argininosuccinate synthase activity (GO:0004055)|
|Biological process||arginine biosynthetic process (GO:0006526)|
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
The graphic that is shown by default represents the longest sequence with a given architecture. Each row contains the following information:
- 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
- a link to the page in the Pfam site showing information about the sequence that the graphic describes
- the UniProt description of the protein sequence
- the number of residues in the sequence
- the Pfam graphic itself.
Note that you can see the family page for a particular domain by clicking on the graphic. You can also choose to see all sequences which have a given architecture by clicking on the Show link in each row.
Finally, because some families can be found in a very large number of architectures, we load only the first fifty architectures by default. If you want to see more architectures, click the button at the bottom of the page to load the next set.
Loading domain graphics...
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...
There are various ways to view or download the sequence alignments that we store. We provide several sequence viewers and a plain-text Stockholm-format file for download.
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 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:
- a Java applet developed at the University of Dundee. You will need Java installed before running jalview
- an HTML page showing the whole alignment.Please note: full Pfam alignments can be very large. These HTML views are extremely large and often cause problems for browsers. Please use either jalview or the Pfam viewer if you have trouble viewing the HTML version
- an HTML-based representation of the alignment, coloured according to the posterior-probability (PP) values from the HMM. As for the standard HTML view, heatmap alignments can also be very large and slow to render.
- Pfam viewer
- an HTML-based viewer that uses DAS to retrieve alignment fragments on request
You can download (or view in your browser) a text representation of a Pfam alignment in various formats:
You can also change the order in which sequences are listed in the alignment, change how insertions are represented, alter the characters that are used to represent gaps in sequences and, finally, choose whether to download the alignment or to view it in your browser directly.
You may find that large alignments cause problems for the viewers and the reformatting tool, so we also provide all alignments in Stockholm format. You can download either the plain text alignment, or a gzipped version of it.
We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.
1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
Format an alignment
We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.
You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.
MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.
HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...
If you find these logos useful in your own work, please consider citing the following article:
This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.
Note: You can also download the data file for the tree.
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.
|Seed source:||Pfam-B_888 (release 2.1)|
|Number in seed:||12|
|Number in full:||4339|
|Average length of the domain:||374.20 aa|
|Average identity of full alignment:||40 %|
|Average coverage of the sequence by the domain:||92.38 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||14|
|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
This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the More....
This chart is a modified "sunburst" visualisation of the species tree for this family. It shows each node in the tree as a separate arc, arranged radially with the superkingdoms at the centre and the species arrayed around the outermost ring.
How the sunburst is generated
The tree is built by considering the taxonomic lineage of each sequence that has a match to this family. For each node in the resulting tree, we draw an arc in the sunburst. The radius of the arc, its distance from the root node at the centre of the sunburst, shows the taxonomic level ("superkingdom", "kingdom", etc). The length of the arc represents either the number of sequences represented at a given level, or the number of species that are found beneath the node in the tree. The weighting scheme can be changed using the sunburst controls.
In order to reduce the complexity of the representation, we reduce the number of taxonomic levels that we show. We consider only the following eight major taxonomic levels:
Colouring and labels
Segments of the tree are coloured approximately according to their superkingdom. For example, archeal branches are coloured with shades of orange, eukaryotes in shades of purple, etc. The colour assignments are shown under the sunburst controls. Where space allows, the name of the taxonomic level will be written on the arc itself.
As you move your mouse across the sunburst, the current node will be highlighted. In the top section of the controls panel we show a summary of the lineage of the currently highlighed node. If you pause over an arc, a tooltip will be shown, giving the name of the taxonomic level in the title and a summary of the number of sequences and species below that node in the tree.
Anomalies in the taxonomy tree
There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.
Missing taxonomic levels
Some species in the taxonomic tree may not have one or more of the main eight levels that we display. For example, Bos taurus is not assigned an order in the NCBI taxonomic tree. In such cases we mark the omitted level with, for example, "No order", in both the tooltip and the lineage summary.
Unmapped species names
The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.
So that these nodes are not simply omitted from the sunburst tree, we group them together in a separate branch (or segment of the sunburst tree). Since we cannot determine the lineage for these unmapped species, we show all levels between the superkingdom and the species as "uncategorised".
Since we reduce the species tree to only the eight main taxonomic levels, sequences that are mapped to the sub-species level in the tree would not normally be shown. Rather than leave out these species, we map them instead to their parent species. So, for example, for sequences belonging to one of the Vibrio cholerae sub-species in the NCBI taxonomy, we show them instead as belonging to the species Vibrio cholerae.
Too many species/sequences
For large species trees, you may see blank regions in the outer layers of the sunburst. These occur when there are large numbers of arcs to be drawn in a small space. If an arc is less than approximately one pixel wide, it will not be drawn and the space will be left blank. You may still be able to get some information about the species in that region by moving your mouse across the area, but since each arc will be very small, it will be difficult to accurately locate a particular species.
The tree shows the occurrence of this domain across different species. More...
We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.
Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.
If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.
For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.
We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.
Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.
We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.
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
Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.
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 Arginosuc_synth domain has been found. There are 37 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...