The Mcm467 complex of Saccharomyces cerevisiae is preferentially activated by autonomously replicating DNA sequences.

We have analyzed the role of single-stranded DNA (ssDNA) in the modulation of the ATPase activity of Mcm467 helicase of the yeast Saccharomyces cerevisiae. The ATPase activity of the Mcm467 complex is modulated in a sequence-specific manner and that the ssDNA sequences derived from the origin of DNA replication of S. cerevisiae autonomously replicating sequence 1 (ARS1) are the most effective stimulators.

Control of ATP-dependent binding of Saccharomyces cerevisiae origin recognition complex to autonomously replicating DNA sequences.

Eukaryotic origin recognition complexes (ORCs) play pivotal roles in the initiation of chromosomal DNA replication. ORC from the yeast, Saccharomyces cerevisiae, recognizes and binds replication origins in the late G1 phase and the binding has profound implications in the progression of the cell cycle to the S-phase. Therefore, we have quantitatively analyzed the mechanism of recognition and interaction of the yeast ORC with various elements of a yeast origin of DNA replication, the autonomously replicating sequence 1 (ARS1).

Mechanism and stoichiometry of interaction of DnaG primase with DnaB helicase of Escherichia coli in RNA primer synthesis.

Initiation and synthesis of RNA primers in the lagging strand of the replication fork in Escherichia coli requires the replicative DnaB helicase and the DNA primase, the DnaG gene product. In addition, the physical interaction between these two replication enzymes appears to play a role in the initiation of chromosomal DNA replication. In vitro, DnaB helicase stimulates primase to synthesize primers on single-stranded (ss) oligonucleotide templates.

Subunit interactions in the assembly of Saccharomyces cerevisiae DNA polymerase alpha.

Eukaryotic DNA polymerase (pol) alpha is a complex of four subunits. The subunits in the yeast Saccharomyces cerevisiae are: 167, 79, 62 and 48 kDa polypeptides. The p79 subunit has no known enzymatic functions, but it is essential for growth and chromosomal DNA replication.

Free radical studies of ellagic acid, a natural phenolic antioxidant.

Ellagic acid, a plant-derived polyphenol, inhibits gamma-radiation (hydroxyl radical) induced lipid peroxidation in rat liver microsomes in a dose- and concentration-dependent manner. Its antioxidant capacity has been estimated using the 1,1-diphenyl-2-picrylhydrazyl radical assay. To understand the actual mechanisms involved in antioxidant activity and the free radical scavenging ability,a nanosecond pulse radiolysis technique has been employed.