LAUSR

To enable chromosomal replication, DNA is unwound by the ATPase molecular motor replicative helicase. The bacterial helicase DnaB is a ring‐shaped homo‐hexamer whose conformational dynamics are being studied through its different 3D structural states adopted along its functional cycle. Our findings describe a new crystal structure for the apo‐DnaB from Vibrio cholerae, forming a planar hexamer with pseudo‐symmetry, constituted by a trimer of dimers in which the C‐terminal domains delimit a triskelion‐shaped hole. This hexamer is labile and inactive. We suggest that it represents an intermediate state allowing the formation of the active NTP‐bound hexamer from dimers.