title: Structural study of immunoaffinity-purified DNA polymerase alpha-DNA primase complex from calf thymus.
abstract: The DNA polymerase alpha-DNA primase complex was purified over 17,000-fold to near homogeneity from calf thymus using an immunoaffinity column. Sodium dodecyl sulfate gel electrophoresis revealed three polypeptides with molecular weights of 140, 50 and 47 kDa, in a ratio of 1:2:0.25. The complex showed a sedimentation coefficient of 9.7 S, a Stokes radius of 56 A and a native molecular weight of 250-260 kDa. Taken together, the data suggest that the calf thymus dNA polymerase alpha-DNA primase complex is essentially a heterotrimer of large (140 kDa) and small (50 kDa) subunits in a ratio of 1:2, with a globular conformation. Electron-microscopic studies of the complex revealed a spherical particle of 120 A in diameter, in agreement with the physiochemical results. The binding of the complex to DNA was also demonstrated.
authors.affiliation: Laboratory of Cancer Cell Biology, Nagoya University School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tamai
authors.forename: K
authors.initials: K
authors.lastname: Kojima
authors.forename: T
authors.initials: T
authors.lastname: Hanaichi
authors.forename: S
authors.initials: S
authors.lastname: Masaki
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Umekawa
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D002417:Cattle; D002846:Chromatography, Affinity; D019915:DNA Primase; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D008970:Molecular Weight; D011487:Protein Conformation; D012316:RNA Nucleotidyltransferases / Q000302:isolation & purification* / Q000378:metabolism; D013950:Thymus Gland / Q000201:enzymology*
chemical_list: D046911:Macromolecular Substances; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases