Formation of DNA adducts with cholyl adenylate, a putative intermediate for biosynthesis of cholyl-CoA.
Cholyl adenylate is a putative intermediate for biosynthesis of cholic acid-coenzyme A (CoA) thioester conjugates by acyl-CoA synthetase. Early studies showed the conjugated acid anhydride moiety of cholyl adenylate to be reactive, attacking proteins to form protein-cholic acid adducts. In the present study, to clarify reactions of cholyl adenylate with DNA under physiological conditions, products with nucleosides were analyzed. HPLC-MS analyses indicated cholyl adenylate to primarily attack hydroxy groups of ribose moieties of nucleosides. Moreover, as speculated from UV and MS studies, exocyclic amino groups of 2'-deoxycytidine and 2'-deoxyadenosine were found to serve as targets of cholyl adenylate; the corresponding cholic amides, N4-cholyl-2'-deoxycytidine and N6-cholyl-2'-deoxyadenosine, were formed at yields of 0.32 and 0.06%, respectively. Structures of these base modified adducts were confirmed by direct comparison with synthetic compounds obtained from coupling reactions of cholic acid with each nucleoside in the presence of dicyclohexylcarbodiimide in pyridine at 70 degrees C. N4-Cholyl-2'-deoxycytidine was also obtained at a level of 1.6 adducts per 10(5) nucleosides from enzymatic hydrolysates of calf thymus DNA reacted with cholyl adenylate. These results suggest that cholyl adenylate, released from CoA synthetase, may have some possibility as a DNA modifier in vivo.
Takamura-Enya
Takeji
T
Cancer Prevention Basic Research Project, National Cancer Center Research Institute, 5-1-1 Tsukiji, Tokyo 104-0045, Japan. tenya@gan2.res.ncc.go.jp
Mano
Nariyasu
N
Kawahara
Nobuo
N
Goto
Junichi
J
Wakabayashi
Keiji
K
D000214:Acyl Coenzyme A / Q000096:biosynthesis*; D000249:Adenosine Monophosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D002793:Cholic Acids / Q000096:biosynthesis* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000378:metabolism*; D018736:DNA Adducts / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D021241:Spectrometry, Mass, Electrospray Ionization
D000214:Acyl Coenzyme A; D002793:Cholic Acids; D018736:DNA Adducts; C117584:cholyl-adenylate; C117585:cholyl-coenzyme A; D000249:Adenosine Monophosphate; D004247:DNA