Cover image

Cover Crystal structures of the inactive and active forms of the AAA+ ATPase domain of the prokaryotic transcriptional activator, NtrC1. Shown here are surface representations of NtrC1 changing from its inactive dimer (upper right) to active oligomer (lower left) form, including inferred models of transient intermediate structures. The off-state dimers (partners colored yellow and blue) are composed of regulatory and ATPase domains. The active ATPase domain alone crystalized as a ring-shaped heptamer, the regulatory domains (whose positions are not known) are not shown. (For details, see Lee et al., p. 2552.)