Ap3A and Ap4A are primers for oligoadenylate synthesis catalyzed by interferon-inducible 2-5A synthetase.
The biological role of Ap3A synthesized in cells by tryptophanyl-tRNA synthetase (WRS) is unknown. Previously we have demonstrated that the cellular level of Ap3A significantly increases after interferon treatment. Here we show that the human 46 kDa 2-5A synthetase efficiently utilizes Ap3A as a primer for oligoadenylate synthesis. The Km for Ap3A is several-fold lower than for Ap4A and 100-fold lower than for ATP. This implies that Ap3A might be a natural primer for the 2'-adenylation reaction catalysed by 2-5A synthetase. Since WRS and 2-5A synthetase are both interferon-inducible proteins, a new link between two interferon-dependent enzymes is established.
Turpaev
K
K
Department of Molecular and Structural Biology, Aarhus University, Denmark.
Hartmann
R
R
Kisselev
L
L
Justesen
J
J
D015088:2',5'-Oligoadenylate Synthetase / Q000378:metabolism*; D000227:Adenine Nucleotides / Q000096:biosynthesis*; D000255:Adenosine Triphosphate / Q000378:metabolism; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D015226:Dinucleoside Phosphates / Q000378:metabolism*; D006801:Humans; D007372:Interferons / Q000494:pharmacology*; D007700:Kinetics; D009843:Oligoribonucleotides / Q000096:biosynthesis*; D014369:Tryptophan-tRNA Ligase / Q000302:isolation & purification / Q000378:metabolism*
D000227:Adenine Nucleotides; D015226:Dinucleoside Phosphates; D009843:Oligoribonucleotides; C020733:diadenosine tetraphosphate; C011440:diadenosine triphosphate; C023505:2',5'-oligoadenylate; D000255:Adenosine Triphosphate; D007372:Interferons; D015088:2',5'-Oligoadenylate Synthetase; D014369:Tryptophan-tRNA Ligase