Crystallographic studies on geminin/CDT1 complex, proteins involved in DNA replication

Abstract

The replication of chromosomal DNA is central for the duplication of a cell. In eukaryotes, a conserved mechanism operates to restrict DNA replication to only once per cell cycle. This requirement is regulated by the geminin/Cdt1 complex. Cdt1 is essential for the recruitment of minichromosome maintenance (MCM) 2-7 complex to the chromatin for DNA replication and establishes the target for the replication inhibitor geminin. To clarify the precise mechanism by which Geminin regulates Cdt1, structural information will prove useful in elucidating how Cdt1 and Geminin interact at the protein level. We identified, cloned and expressed (in bacterial cells) the geminin-binding domain of human Cdt1 and purified it to homogeneity. This hCdt1 fragment and its complex with geminin have both been set up for crystallization. This research can provide potential insight on the regulation of DNA replication.