Comparison of the ADP-ribosylating thermozyme from Sulfolobus solfataricus and the mesophilic poly(ADP-ribose) polymerases.
The poly(ADP-ribose) polymerase-like thermozyme purified from Sulfolobus solfataricus was characterised with respect to some physico-chemical properties. The archaeal protein exhibited a scarce electrophoretic mobility at both pH 2.9 and pH 7.5. Determination of the isoelectric point (pI=7.0-7.2) allowed us to understand the reason for the limited migration at pH 7.5, while amino acid composition analysis showed a moderate content of basic residues, which reduced mobility at pH 2.9. With respect to the charge, the archaeal enzyme behaved differently from the eukaryotic thermolabile poly(ADP-ribose) polymerase, described as a basic protein (pI=9.5). Well known inhibitors of the mesophilic polymerase like Zn(2+), nicotinamide and 3-aminobenzamide exerted a smaller effect on the enzyme from S. solfataricus, reducing the activity by at most 50%. Mg(2+) was a positive effector, although in a dose-dependent manner. It influenced the fluorescence spectrum of the archaeal protein, whereas NaCl had no effect.
Faraone Mennella
M R
MR
Dipartimento di Chimica Organica e Biologica, Facoltà di Scienze, Università Federico II, Naples, Italy.
Castellano
S
S
De Luca
P
P
Discenza
A
A
Gambacorta
A
A
Nicolaus
B
B
Farina
B
B
D000596:Amino Acids / Q000032:analysis; D002413:Cations, Divalent / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D007525:Isoelectric Focusing; D008970:Molecular Weight; D011065:Poly(ADP-ribose) Polymerases / Q000737:chemistry* / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D016944:Sulfolobus / Q000201:enzymology*
D000596:Amino Acids; D002413:Cations, Divalent; D011065:Poly(ADP-ribose) Polymerases