Investigating protein-protein interfaces in bacterial transcription complexes: A fragmentation approach

Abstract

Transcription initiation by σ54-RNA polymerase (RNAP) relies explicitly on a transient interaction with a complex molecular machine belonging to the AAA+ (ATPases associated with various cellular activities) superfamily. Members of the AAA+ superfamily convert chemical energy derived from NTP hydrolysis to a mechanical force used to remodel their target substrate. Recently Bordes and colleagues, using a protein fragmentation approach, identified a unique sequence within σ54-dependent transcriptional activators that constitutes a σ54-binding interface. This interface is not static, but subject to nucleotide-dependent movement which may represent a common mechanism for controlling output that has been adopted by other AAA+ proteins. © 2003 Wiley Periodicals, Inc.