Interaction of heliquinomycin with single-stranded DNA inhibits MCM4/6/7 helicase.
The antibiotic heliquinomycin inhibited cellular DNA replication at IC(50) of 2.5 µM without affecting level of chromatin-bound MCM4 and without activating the DNA replication stress checkpoint system, suggesting that heliquinomycin perturbs DNA replication mainly by inhibiting the activity of replicative DNA helicase that unwinds DNA duplex at replication forks. Among the DNA helicases involved in DNA replication, DNA helicase B was inhibited by heliquinomycin at IC(50) of 4.3 µM and RECQL4 helicase at IC(50) of 14 µM; these values are higher than that of MCM4/6/7 helicase (2.5 µM). These results suggest that heliquinomycin mainly targets actions of the replicative DNA helicases. Gel-retardation experiment indicates that heliquinomycin binds to single-stranded DNA. The single-stranded DNA-binding ability of MCM4/6/7 was affected in the presence of heliquinomycin. The data suggest that heliquinomycin inhibits the DNA helicase activity of MCM4/6/7 complex by stabilizing its interaction with single-stranded DNA.
College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan.
Takafumi
T
Sugiyama
Makoto
M
Chino
Toshiki
T
Tsurimoto
Naohito
N
Nozaki
Yukio
Y
Ishimi
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism*; D016227:Benzoquinones / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D004265:DNA Helicases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D004261:DNA Replication / Q000187:drug effects; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; 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 / Q000037:antagonists & inhibitors / Q000378:metabolism; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D013141:Spiro Compounds / Q000737:chemistry / Q000378:metabolism
D000900:Anti-Bacterial Agents; D016227:Benzoquinones; D018797:Cell Cycle Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D013141:Spiro Compounds; C101772:heliquinomycin; C484263:HELB protein, human; 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