Acidic phospholipids with unsaturated fatty acids inhibit the binding of origin recognition complex to origin DNA.
Origin Recognition Complex (ORC) is a candidate initiator of chromosomal DNA replication in eukaryotes. We recently reported that cardiolipin inhibits the interaction of Origin Recognition Complex ORC with origin DNA, as is the case of DnaA, the initiator of chromosomal DNA replication in prokaryotes. We report here that another acidic phospholipid, phosphatidylglycerol (PG), also inhibits the interaction. Synthetic PG with only unsaturated fatty acids inhibits ORC-binding to origin DNA more strongly than PG with only saturated fatty acids. On the other hand, phosphatidylcholine (neutral phospholipid) does not affect the ORC-origin interaction, regardless of the presence of saturated or unsaturated fatty acids. These results suggest that an acidic moiety and unsaturated fatty acids are important factors for the inhibitory effect of phospholipids on ORC binding to origin DNA, as is the case for DnaA. The inhibitory effect of cardiolipin on ORC binding to origin DNA was more apparent at 30 degrees C than at 4 degrees C. Furthermore, chlorpromazine restored the ORC-origin interaction in the presence of cardiolipin. Since the presence of unsaturated fatty acids, low incubation temperatures, and the addition of chlorpromazine all decrease membrane fluidity, these results suggest that membrane fluidity is important for the inhibitory effect of acidic phospholipids on ORC-binding to origin DNA, as is the case for DnaA.
Lee
Jong-Ryul
JR
Faculty of Pharmaceutical Sciences, Okayama University, 700-8530, Japan.
Takenaka
Hitomi
H
Takahashi
Naoko
N
Makise
Masaki
M
Yamaguchi
Yoshihiro
Y
Tsuchiya
Tomofusa
T
Mizushima
Tohru
T
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002308:Cardiolipins / Q000378:metabolism; D002460:Cell Line; D002746:Chlorpromazine / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D007313:Insecta; D010743:Phospholipids / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D018741:Replication Origin; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
D002308:Cardiolipins; D018492:Dopamine Antagonists; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D000255:Adenosine Triphosphate; D004247:DNA; D002746:Chlorpromazine