title: Inhibition of eukaryotic DNA polymerase alpha with a novel lysophosphatidic acid (PHYLPA) isolated from myxoamoebae of Physarum polycephalum.
abstract: A specific inhibitor of DNA polymerase alpha was isolated from the lipid fraction prepared from myxoamoebae of a true slime mold, Physarum polycephalum. The purified substance was subjected to structural studies by fast atom bombardment mass spectroscopy, infrared spectroscopy, and two-dimensional nuclear magnetic resonance spectroscopy. The structure of this substance was thereby suggested to be a novel lysophosphatidic acid (LPA) composed of cyclic phosphate and cyclopropane-containing hexadecanoic acid. Then we named this substance PHYLPA (Physarum LPA). PHYLPA inhibited more than 80% of the affinity-purified calf thymus DNA polymerase alpha activity at a concentration of 10 micrograms/ml (approximately 20 microM). Inhibition was observed for DNA polymerase alpha but not for DNA polymerase beta or gamma from various eukaryotic species, nor did it inhibit DNA polymerase I from E. coli. From kinetic analyses, the inhibition was considered to be caused by the interaction of PHYLPA with the template DNA.
authors.affiliation: Department of Biology, Faculty of Science, Ochanomizu University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Murakami-Murofushi
authors.forename: M
authors.initials: M
authors.lastname: Shioda
authors.forename: K
authors.initials: K
authors.lastname: Kaji
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
authors.forename: H
authors.initials: H
authors.lastname: Murofushi
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004257:DNA Polymerase II / Q000037:antagonists & inhibitors*; D004271:DNA, Fungal / Q000096:biosynthesis; D008246:Lysophospholipids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D016839:Physarum polycephalum / Q000737:chemistry / Q000201:enzymology*; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013055:Spectrophotometry, Infrared
chemical_list: D004271:DNA, Fungal; D008246:Lysophospholipids; D004257:DNA Polymerase II