Formation of MgF3−-dependent complexes between an AAA+ ATPase and σ54

The widely distributed bacterial σ54-dependent transcription regulates pathogenicity and numerous adaptive responses in diverse bacteria. Formation of the σ54-dependent open promoter complex is a multi-step process driven by AAA+ ATPases. Non-hydrolysable nucleotide analogues are particularly suitable for studying such complexity by capturing various intermediate states along the energy coupling pathway. Here we report a novel ATP analogue, ADP–MgF3−, which traps an AAA+ ATPase with its target σ54. The MgF3−-dependent complex is highly homogeneous and functional assays suggest it may represent an early transcription intermediate state valuable for structural studies.

▸ Novel ATP analogue ADP–MgF3− traps an AAA+ ATPase with its target σ54. ▸ MgF3−-dependent complex forms a highly homogenous population. ▸ MgF3−-dependent complex represents an early transcription intermediate state.