Adenylosuccinate synthase

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Adenylosuccinate synthase
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Adenylosuccinate synthetase dimer, Human
Identifiers
EC number6.3.4.4
CAS number9023-57-8
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
Adenylsucc_synt
File:PDB 1dj3 EBI.jpg
structures of adenylosuccinate synthetase from triticum aestivum and arabidopsis thaliana
Identifiers
SymbolAdenylsucc_synt
PfamPF00709
Pfam clanCL0023
InterProIPR001114
PROSITEPDOC00444
SCOP1ade
SUPERFAMILY1ade

In molecular biology, Adenylosuccinate synthase (or adenylosuccinate synthetase) (EC 6.3.4.4.) is an enzyme that plays an important role in purine biosynthesis, by catalysing the guanosine triphosphate (GTP)-dependent conversion of inosine monophosphate (IMP) and aspartic acid to guanosine diphosphate (GDP), phosphate and N(6)-(1,2-dicarboxyethyl)-AMP. Adenylosuccinate synthetase has been characterised from various sources ranging from Escherichia coli (gene purA) to vertebrate tissues. In vertebrates, two isozymes are present: one involved in purine biosynthesis and the other in the purine nucleotide cycle.

Structure

The crystal structure of adenylosuccinate synthetase from E. coli reveals that the dominant structural element of each monomer of the homodimer is a central beta-sheet of 10 strands. The first nine strands of the sheet are mutually parallel with right-handed crossover connections between the strands. The 10th strand is antiparallel with respect to the first nine strands. In addition, the enzyme has two antiparallel beta-sheets, composed of two strands and three strands each, 11 alpha-helices and two short 3/10-helices. Further, it has been suggested that the similarities in the GTP-binding domains of the synthetase and the p21ras protein are an example of convergent evolution of two distinct families of GTP-binding proteins.[1] Structures of adenylosuccinate synthetase from Triticum aestivum and Arabidopsis thaliana when compared with the known structures from E. coli reveals that the overall fold is very similar to that of the E. coli protein.[2]

Isozymes

Humans express two adenylosuccinate synthase isozymes:

adenylosuccinate synthase
Identifiers
SymbolADSS
Entrez159
HUGO292
OMIM103060
RefSeqNM_001126
UniProtP30520
Other data
EC number6.3.4.4
LocusChr. 1 q44
adenylosuccinate synthase like 1
Identifiers
SymbolADSSL1
Entrez122622
HUGO20093
OMIM612498
RefSeqNM_152328
UniProtQ8N142
Other data
EC number6.3.4.4
LocusChr. 14 q32.33

External links

References

  1. Poland BW, Silva MM, Serra MA, Cho Y, Kim KH, Harris EM, Honzatko RB (December 1993). "Crystal structure of adenylosuccinate synthetase from Escherichia coli. Evidence for convergent evolution of GTP-binding domains". J. Biol. Chem. 268 (34): 25334–42. PMID 8244965.
  2. Prade L, Cowan-Jacob SW, Chemla P, Potter S, Ward E, Fonne-Pfister R (February 2000). "Structures of adenylosuccinate synthetase from Triticum aestivum and Arabidopsis thaliana". J. Mol. Biol. 296 (2): 569–77. doi:10.1006/jmbi.1999.3473. PMID 10669609.
This article incorporates text from the public domain Pfam and InterPro: IPR001114

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