Structure/function of the primosome in DNA replication

University Of Wisconsin-Madison, Madison WI

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Abstract

[unreadable] DESCRIPTION (provided by applicant): [unreadable] Completing DNA synthesis in the face of DNA damage is a problem that all organisms must solve in order to faithfully replicate their genomes during normal growth and development. In E. coli, it is estimated that replication complexes formed at the origin of replication are capable of synthesizing only a fraction of the bacterial chromosome before dissociating from the template DMA. A collection of proteins referred to as the primosome complex, composed of PriA, PriB, PriC, DnaB, DnaC, DnaT, and DnaG proteins, functions in E. coli to reload DNA synthesis enzymes onto stalled replication forks. The primosome collectively supports critical activities such as recognizing and binding abandoned DNA replication fork structures, unwinding duplex DNA, and synthesizing short oligonucleotides to prime DNA synthesis. However, the molecular mechanisms that govern activity of the primosome in these fundamental biological processes remain poorly understood. The goals of this proposal are to 1) define the domain structure of the primosome initiator protein, PriA; 2) determine the structure of PriA by x-ray crystallography; and 3) probe the structural basis for the functions of other members of the primosome using x-ray crystallography and other biochemical approaches. Detailed knowledge of the structure of PriA and other primosome proteins will help elucidate the mechanisms used by the primosome enzyme complex in DNA replication restart and will provide insight into a biological process critical for maintaining genomic stability. [unreadable] [unreadable] [unreadable]