Table 1.

Summary of the biochemical properties of mutants of Cdt1 protein.

		WT	RR-AA	R-S	R-C
DNA replication		++	++++	+	+
Licensing activity		++	++++	+	+
Complex formation with Mcm2˜7		++	++	−	−
Complex formation with Geminin		++	−	++	++
Stimulation of MCM helicase		++	++	++	++
DNA-binding activity		++	++	++	++
Kinase activity	Cdk2/Cyclin A	++	++	++	++
	Cdc2/Cyclin B	++	+/++	+++	+++
	Cdc7/Dbf4	++	+	+++	+++

The assays were performed as described in Materials and Methods. The activity of the wild type Cdt1 is indicated as ++ in each assay; the activities of mutant Cdt1 proteins are shown by the number of plus signs. No activity is shown as a minus sign.