Table 1. Structural states of the DnaB hexamer in complex with various helicase loaders and their loading mechanisms.

Complex	Stoichiometry	Origin of the helicase	Origin of the loader	PDB code	Resolution (Å)	Helicase ring state	Loading mechanism
DnaB·DnaI·DnaG	6:6:3	Geobacillus stearothermophilus	Bacillus subtilis	4m4w	6.10	Closed and dilated planar	Ring-maker
DnaB·DnaC	6:6	Escherichia coli	Escherichia coli	6qel	3.90	Open helical	Ring-breaker
DnaB·λP	6:5	Escherichia coli	Phage λ	6bbm	4.10	Open helical	Ring-breaker