Ap4A is not an efficient Zn(II) binding agent. A concerted potentiometric, calorimetric and NMR study.
Diadenosine 5',5''-P(1)P(4) tetraphosphate (Ap(4)A) has been considered as an intracellular partner for Zn(II). We applied potentiometry, ITC and NMR to study protonation equilibria of Ap(4)A and Zn(II) complexation by this dinucleotide. The values of binding constants obtained by these three techniques under various experimental conditions coherently demonstrated that Ap(4)A binds Zn(II) weakly, with an apparent binding constant of ca. 10(4) at neutral pH. Such a low stability of Zn(II) complexes with Ap(4)A excludes a possibility for interactions between these two agents in vivo.
Wszelaka-Rylik
Małgorzata
M
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland.
Witkiewicz-Kucharczyk
Aleksandra
A
Wójcik
Jacek
J
Bal
Wojciech
W
D002151:Calorimetry; D002712:Chlorides / Q000737:chemistry*; D015226:Dinucleoside Phosphates / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D011199:Potentiometry; D017967:Zinc Compounds / Q000737:chemistry*
D002712:Chlorides; D015226:Dinucleoside Phosphates; D017967:Zinc Compounds; C020733:diadenosine tetraphosphate; C016837:zinc chloride