A nonenzymatic modification of the amino-terminal domain of histone H3 by bile acid acyl adenylate.
Although it has been proposed that the secondary bile acids, deoxycholic acid and lithocholic acid, increase the number of aberrant crypt foci in the colon and may act as colon tumor promoters, there is little evidence detailing their mechanism of action. Histones play an important role in controlling gene expression, and the posttranslational modification of histones plays a role in regulation of intracellular signal transduction. In particular, the amino-terminal tail domain of histone H3 is sensitive to several posttranslational modifications, and acetylation of this domain changes its electrostatic environment and results in the loss of native folding. Therefore, we studied the modification of epsilon-amino groups on human histone H3 by deoxycholyl adenylate, which is an active intermediate in deoxycholyl thioester biosynthesis. After incubation of recombinant human histone H3 with a smaller amount of acyl adenylate, followed by enzymatic digestion, the peptide fragment mixtures were analyzed by matrix-assisted laser desorption ionization mass spectrometry. These data showed the formation of only one adduct fragment, which corresponded to amino acids 3-8 with a deoxycholate adduct, suggesting that the epsilon-amino group of Lys(4) had the highest reactivity. This novel modification, formation of a bile acid adduct on the histone H3 amino-terminal tail domain through an active acyl adenylate, may relate to the carcinogenesis-promoting effects of secondary bile acids.
Graduate School of Pharmaceutical Sciences, Tohoku University, 101 Seiryo-machi, Aobayama, Aoba-ku, Sendai 980-8578, Japan.
Nariyasu
N
Mano
Kie
K
Kasuga
Norihiro
N
Kobayashi
Junichi
J
Goto
D000595:Amino Acid Sequence; D001647:Bile Acids and Salts / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D018736:DNA Adducts; D003840:Deoxycholic Acid / Q000737:chemistry; D006657:Histones / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007477:Ions; D008239:Lysine / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D015398:Signal Transduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature
D001647:Bile Acids and Salts; D018736:DNA Adducts; D006657:Histones; D007477:Ions; D011994:Recombinant Proteins; D003840:Deoxycholic Acid; D008239:Lysine