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
310-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:
^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.
PMID10669609.
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
310-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:
^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.
PMID10669609.