title: Regulation of the enzymatic catalysis of poly(ADP-ribose) polymerase by dsDNA, polyamines, Mg2+, Ca2+, histones H1 and H3, and ATP.
abstract: The enzymatic mechanism of poly(ADP-ribose) polymerase (PARP-1) has been analyzed in two in vitro systems: (a) in solution and (b) when the acceptor histones were attached to a solid surface. In system (a), it was established that the coenzymatic function of dsDNAs was sequence-independent. However, it is apparent from the calculated specificity constants that the AT homopolymer is by far the most effective coenzyme and randomly damaged DNA is the poorest. Rates of auto(poly-ADP-ribosylation) with dsDNAs as coenzymes were nearly linear for 20 min, in contrast to rates with dcDNA, which showed product [(ADPR)n] inhibition. An allosteric activation of auto(poly-ADP-ribosylation) by physiologic cellular components, Mg2+, Ca2+, and polyamines, was demonstrated, with spermine as the most powerful activator. On a molar basis, histones H(1) and H(3) were the most effective PARP-1 activators, and their action was abolished by acetylation of lysine end groups. It was shown in system (b) that oligo(ADP-ribosyl) transfer to histone H(1) is 1% of that of auto(poly-ADP-ribosylation) of PARP-1, and this trans(ADP-ribosylation) is selectively regulated by putrescine (activator). Physiologic cellular concentrations of ATP inhibit PARP-1 auto(poly-ADP-ribosylation) but less so the transfer of oligo(ADP-ribose) to histones, indicating that PARP-1 auto(ADP-ribosylation) activity is dormant in bioenergetically intact cells, allowing only trans(ADP-ribosylation) to take place. The inhibitory mechanism of ATP on PARP-1 consists of a noncompetitive interaction with the NAD site and competition with the coenzymic DNA binding site. A novel regulation of PARP-1 activity and its chromatin-related functions by cellular bioenergetics is proposed that occurs in functional cells not exposed to catastrophic DNA damage.
authors.affiliation: Department of Anatomy, University of California-San Francisco, San Francisco, CA 94143, USA. cmkun@comcast.net
authors.forename: Ernest
authors.initials: E
authors.lastname: Kun
authors.forename: Eva
authors.initials: E
authors.lastname: Kirsten
authors.forename: Jerome
authors.initials: J
authors.lastname: Mendeleyev
authors.forename: Charles P
authors.initials: CP
authors.lastname: Ordahl
mesh_terms: D000227:Adenine Nucleotides / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000737:chemistry*; D000494:Allosteric Regulation; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000737:chemistry*; D002384:Catalysis; D002413:Cations, Divalent / Q000737:chemistry; D002417:Cattle; D003067:Coenzymes / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000737:chemistry; D006657:Histones / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry*; D009843:Oligoribonucleotides / Q000737:chemistry; D011064:Poly Adenosine Diphosphate Ribose / Q000737:chemistry; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000737:chemistry* / Q000378:metabolism*; D011073:Polyamines / Q000737:chemistry*; D012995:Solubility; D013096:Spermine / Q000737:chemistry
chemical_list: D000227:Adenine Nucleotides; D002413:Cations, Divalent; D003067:Coenzymes; D020536:Enzyme Activators; D006657:Histones; D009843:Oligoribonucleotides; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011073:Polyamines; D011064:Poly Adenosine Diphosphate Ribose; D013096:Spermine; C023505:2',5'-oligoadenylate; D000255:Adenosine Triphosphate; D004247:DNA; D011065:Poly(ADP-ribose) Polymerases; D008274:Magnesium; D002118:Calcium