Adenylosuccinate synthase

Adenylosuccinate synthase
Adenylosuccinate synthetase dimer, Human
Identifiers
EC number 6.3.4.4
CAS number 9023-57-8
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO
Adenylsucc_synt
structures of adenylosuccinate synthetase from triticum aestivum and arabidopsis thaliana
Identifiers
Symbol Adenylsucc_synt
Pfam PF00709
Pfam clan CL0023
InterPro IPR001114
PROSITE PDOC00444
SCOP 1ade
SUPERFAMILY 1ade

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
Symbol ADSS
Entrez 159
HUGO 292
OMIM 103060
RefSeq NM_001126
UniProt P30520
Other data
EC number 6.3.4.4
Locus Chr. 1 q44
adenylosuccinate synthase like 1
Identifiers
Symbol ADSSL1
Entrez 122622
HUGO 20093
OMIM 612498
RefSeq NM_152328
UniProt Q8N142
Other data
EC number 6.3.4.4
Locus Chr. 14 q32.33

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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