Effect of heliquinomycin on the activity of human minichromosome maintenance 4/6/7 helicase.
The antibiotic heliquinomycin, which inhibits cellular DNA replication at a half-maximal inhibitory concentration (IC(50)) of 1.4-4 microM, was found to inhibit the DNA helicase activity of the human minichromosome maintenance (MCM) 4/6/7 complex at an IC(50) value of 2.4 microM. In contrast, 14 microM heliquinomycin did not inhibit significantly either the DNA helicase activity of the SV40 T antigen and Werner protein or the oligonucleotide displacement activity of human replication protein A. At IC(50) values of 25 and 6.5 microM, heliquinomycin inhibited the RNA priming and DNA polymerization activities, respectively, of human DNA polymerase-alpha/primase. Thus, of the enzymes studied, the MCM4/6/7 complex was the most sensitive to heliquinomycin; this suggests that MCM helicase is one of the main targets of heliquinomycin in vivo. It was observed that heliquinomycin did not inhibit the ATPase activity of the MCM4/6/7 complex to a great extent in the absence of single-stranded DNA. In contrast, heliquinomycin at an IC(50) value of 5.2 microM inhibited the ATPase activity of the MCM4/6/7 complex in the presence of single-stranded DNA. This suggests that heliquinomycin interferes with the interaction of the MCM4/6/7 complex with single-stranded DNA.
College of Science, Ibaraki University, Japan. ishimi@mx.ibaraki.ac.jp
Yukio
Y
Ishimi
Takafumi
T
Sugiyama
Ryou
R
Nakaya
Makoto
M
Kanamori
Toshiyuki
T
Kohno
Takemi
T
Enomoto
Makoto
M
Chino
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D016227:Benzoquinones / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D001973:Bromodeoxyuridine / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D004265:DNA Helicases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004256:DNA Polymerase I / Q000037:antagonists & inhibitors / Q000378:metabolism; D019915:DNA Primase / Q000037:antagonists & inhibitors / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005090:Exodeoxyribonucleases / Q000037:antagonists & inhibitors / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7; D046912:Multiprotein Complexes / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D012313:RNA / Q000235:genetics / Q000378:metabolism; D053484:RecQ Helicases / Q000037:antagonists & inhibitors / Q000378:metabolism; D051716:Replication Protein A / Q000378:metabolism; D013141:Spiro Compounds / Q000494:pharmacology; D000071657:Werner Syndrome Helicase
D016227:Benzoquinones; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; C034477:RNA primers; C497167:RPA1 protein, human; C534779:RPA3 protein, human; D051716:Replication Protein A; D013141:Spiro Compounds; C101772:heliquinomycin; D012313:RNA; D019915:DNA Primase; D004256:DNA Polymerase I; C516794:RPA2 protein, human; D005090:Exodeoxyribonucleases; D000251:Adenosine Triphosphatases; D004265:DNA Helicases; C099243:MCM4 protein, human; C103258:MCM6 protein, human; C101624:MCM7 protein, human; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase; D001973:Bromodeoxyuridine