Summary: Arginosuccinate synthase

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Wikipedia: Argininosuccinate synthase
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Argininosuccinate synthase Edit Wikipedia article

Argininosuccinate synthetase

Crystallographic structure of human argininosuccinate synthetase.^[1]

Identifiers

Databases

PDB structures

AmiGO / EGO

Search
PMC	articles
PubMed	articles
NCBI	proteins

Argininosuccinate synthetase 1
Identifiers
Symbol	ASS1
Entrez	445
HUGO	758
OMIM	603470
RefSeq	NM_000050
UniProt	P00966
Other data
EC number	6.3.4.5
Locus	Chr. 9 q34.1

Reaction catalyzed by argininosuccinate synthetase. Adapted from Goto et al. 2003.^[2]

Argininosuccinate synthetase

crystal structure of thermus thermophilus hb8 argininosuccinate synthetase in complex with atp and citrulline

Identifiers

Symbol

Arginosuc_synth

Pfam clan

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

Argininosuccinate synthase or synthetase (ASS) (EC 6.3.4.5) is an enzyme that catalyzes the synthesis of argininosuccinate from citrulline and aspartate.

ASS is responsible for the third step of the urea cycle and one of the reactions of the citrulline-NO cycle.

Genetic structure[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.^[3]

Enzyme mechanism[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.^[4]

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.^[5]

Enzyme structure[edit]

Quaternary structure

Argininosuccinate synthetase is a homotetramer, with each subunit consisting of 412 residues.^[6] 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.^[7]

Active site

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.^[2] 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.^[8] 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.^[7] The ATP binding domain of argininosuccinate synthetase is similar to that of other N-type ATP pyrophosphatases.^[8]

Active site of argininosuccinate synthetase shown with bound citrulline, ATP, and aspartate interacting with select active site residues. Modeled using PyMol from PDB 1J1Z.

Biological function[edit]

Argininosuccinate synthetase is involved in the synthesis of creatine, polyamines, arginine, urea, and nitric oxide.^[9]

Arginine synthesis

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.^[6]^[9] Genetic defects that cause incorrect localization of argininosuccinate synthetase to the outer mitochondrial membrane cause type II citrullinemia.^[9]

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.^[9]

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.^[10] It has also been demonstrated in vitro that arginine down-regulates argininosuccinate synthetase expression, while citrulline up-regulates it.^[9]

Citrulline-NO cycle

The enzyme endothelial nitric oxide synthase produces nitric oxide from arginine in endothelial cells.^[9] 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.^[6]

In endothelial cells, it has been shown that ASS expression is increased by laminar shear stress due to pulsative blood flow.^[11] Emerging evidence suggests that ASS may also be subject to regulation by phosphorylation at the Ser-328 residue by protein kinase C-Î±^[12] and by nitrosylation at the Cys-132 residue by nitric oxide synthase.^[7]

Role in disease[edit]

Citrullinemia

Citrullinemia is an inherited autosomal recessive disease.^[13] 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.^[14]

Cancer biochemistry

A lack of argininosuccinate synthetase expression has been observed in several types of cancer cells, including pancreatic cancer, liver cancer,^[15] and melanoma.^[16] 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.^[17]

References[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.
^ ^a ^b 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.
^ ^a ^b ^c 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.
^ ^a ^b ^c 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.
^ ^a ^b 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.
^ ^a ^b ^c ^d ^e ^f 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.

External links[edit]

GeneReviews/NCBI/NIH/UW entry on Argininosuccinate Synthetase Deficiency; ASS Deficiency; Argininosuccinic Acid Synthetase Deficiency; CTLN1; Citrullinemia, Classic

Metabolism: amino acid metabolism Â· urea cycle enzymes

Main cycle

mitochondrial matrix: Carbamoyl phosphate synthetase I Â· Ornithine transcarbamylase
cytosol: Argininosuccinate synthetase Â· Argininosuccinate lyase Â· Arginase

Regulatory/transport

N-Acetylglutamate synthase Â· Ornithine translocase

M: MET

mt, k, c/g/r/p/y/i, f/h/s/l/o/e, a/u, n, m

k, cgrp/y/i, f/h/s/l/o/e, au, n, m, epon

m (A16/C10), i (k, c/g/r/p/y/i, f/h/s/o/e, a/u, n, m)

Enzymes: CO CS and CN ligases (EC 6.1-6.3)

6.1: Carbon-Oxygen

Aminoacyl tRNA synthetase
- Tyrosine
- Tryptophan
- Threonine
- Leucine
- Isoleucine
- Lysine
- Alanine
- Valine
- Methionine
- Serine
- Aspartate
- D-alanine-poly(phosphoribitol) ligase
- Glycine
- Proline
- Cysteine
- Glutamate
- Glutamine
- Arginine
- Phenylalanine
- Histidine
- Asparagine
- Aspartate
- Glutamate
- Lysine

6.2: Carbon-Sulfur

Succinyl coenzyme A synthetase - Acetyl Co-A synthetase - Long fatty acyl CoA synthetase

6.3: Carbon-Nitrogen

B
enzm
1.1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 10
- 11
- 13
- 14
- 15-18
2.1
- 2
- 3
- 4
- 5
- 6
- 7
  - 2.7.10
  - 11-12
- 8
3.1
- - 3.1.3.48
- 2
- 3
- 4
  - 3.4.21
  - 22
  - 23
  - 24
- 5
- 6
- 7
4.1
- 2
- 3
- 4
- 5
- 6
5.1
- 2
- 3
- 4
- 99
6.1-3
- 4
- 5-6

Ligases: carbon-carbon ligases (EC 6.4)

Biotin dependent carboxylase

Other

Polyketide synthase

B
enzm
1.1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 10
- 11
- 13
- 14
- 15-18
2.1
- 2
- 3
- 4
- 5
- 6
- 7
  - 2.7.10
  - 11-12
- 8
3.1
- - 3.1.3.48
- 2
- 3
- 4
  - 3.4.21
  - 22
  - 23
  - 24
- 5
- 6
- 7
4.1
- 2
- 3
- 4
- 5
- 6
5.1
- 2
- 3
- 4
- 99
6.1-3
- 4
- 5-6

Enzymes: Phosphoric ester and nitrogen-metal ligases (EC 6.5-6.6)

6.5: Phosphoric Ester

DNA ligase

6.6: Nitrogen-Metal

B
enzm
1.1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 10
- 11
- 13
- 14
- 15-18
2.1
- 2
- 3
- 4
- 5
- 6
- 7
  - 2.7.10
  - 11-12
- 8
3.1
- - 3.1.3.48
- 2
- 3
- 4
  - 3.4.21
  - 22
  - 23
  - 24
- 5
- 6
- 7
4.1
- 2
- 3
- 4
- 5
- 6
5.1
- 2
- 3
- 4
- 99
6.1-3
- 4
- 5-6

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.

Arginosuccinate synthase Provide feedback

This family contains a PP-loop motif [1].

Literature references

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

PANDIT:	PF00764
PROSITE:	PDOC00488
Pseudofam:	PF00764
SCOP:	1kp2
SYSTERS:	Arginosuc_synth

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.

Gene Ontology

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)
Molecular function	argininosuccinate synthase activity (GO:0004055)
Biological process	arginine biosynthetic process (GO:0006526)

Domain organisation

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Pfam Clan

This family is a member of clan HUP (CL0039), which contains the following 26 members:

Arginosuc_synth Asn_synthase ATP-sulfurylase ATP_bind_3 ATP_bind_4 Citrate_ly_lig CTP_transf_2 DNA_photolyase ETF FAD_syn HIGH_NTase1 NAD_synthase Pantoate_ligase PAPS_reduct QueC ThiI tRNA-synt_1 tRNA-synt_1_2 tRNA-synt_1b tRNA-synt_1c tRNA-synt_1d tRNA-synt_1e tRNA-synt_1f tRNA-synt_1g tRNA_Me_trans Usp

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	Seed (12)	Full (4339)	Representative proteomes				NCBI (3498)	Meta (3319)
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Format an alignment

	Seed (12)	Full (4339)	Representative proteomes				NCBI (3498)	Meta (3319)
	Seed (12)	Full (4339)	RP15 (359)	RP35 (740)	RP55 (981)	RP75 (1169)	NCBI (3498)	Meta (3319)
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Sequence:	Inserts lower case All upper case
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	Seed (12)	Full (4339)	RP15 (359)	RP35 (740)	RP55 (981)	RP75 (1169)	NCBI (3498)	Meta (3319)
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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

Seed source:

Pfam-B_888 (release 2.1)

Previous IDs:

none

Type:

Family

Author:

Bateman A

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 information

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	21.0	21.0
Trusted cut-off	21.0	21.0
Noise cut-off	20.9	20.9

Model length:

388

Family (HMM) version:

14

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Species distribution

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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".

Sub-species

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.

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The tree shows the occurrence of this domain across different species. More...

Species trees

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.

Interactive tree

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

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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.

Interactions

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Arginosuc_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 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.

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Archea	Eukaryota
Bacteria	Other sequences
Viruses	Unclassified
Viroids	Unclassified sequence

Family: Arginosuc_synth (PF00764)

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Summary: Arginosuccinate synthase

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Argininosuccinate synthase Edit Wikipedia article

Contents

Genetic structure[edit]

Enzyme mechanism[edit]

Enzyme structure[edit]

Biological function[edit]

Role in disease[edit]

See also[edit]

References[edit]

External links[edit]

Arginosuccinate synthase Provide feedback

Literature references

External database links

InterPro entry IPR001518

Gene Ontology

Domain organisation

Pfam Clan

Alignments

Alignment types

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Format an alignment

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External links

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Trees

Curation and family details

Curation

HMM information

Species distribution

Sunburst controls

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Change the size of the sunburst

Colour assignments

Selections

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How the sunburst is generated

Colouring and labels

Anomalies in the taxonomy tree

Missing taxonomic levels

Unmapped species names

Sub-species

Too many species/sequences

Tree controls

Annotation

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Selected sequences

Species trees

Interactive tree

Interactions

Structures