Papers In Press, published online ahead of print March 6, 2008
J. Biol. Chem, 10.1074/jbc.M800801200
Submitted on January 30, 2008
Revised on March 4, 2008
Accepted on March 4, 2008
An intra-molecular route for coupling ATPase activity in AAA+ proteins for transcription activation
Nicolas Joly, Patricia C. Burrows, and Martin Buck
Division of Biology, Imperial College London, London SW7 2AZ
Corresponding Author: m.buck{at}imperial.ac.uk
AAA+ proteins (ATPases Associated with various cellular Activities) contribute to many cellular processes and typically function as higher-order oligomers permitting the coordination of nucleotide hydrolysis for functional output which leads to substrate remodelling. The precise mechanisms which enable the relay of nucleotide hydrolysis to their specific functional outputs are largely unknown. Here we use PspF, a specialized AAA+ protein required for enhancer-dependent transcription activation in Escherichia coli, as a model system to address this question. We demonstrate that a conserved asparagine is involved in internal organisation of the oligomeric ring, regulation of ATPase activity by "trans" factors and in optimising substrate remodelling. We provide evidence that the spatial relationship between the asparagine residue and the Walker B motif is one key element in the conformational signalling pathway that leads to substrate remodelling. Such functional organisation most likely applies to other AAA+ proteins including Ltag (Simian virus 40), Rep40 (Adeno-associated virus - 2) and p97 (Mus musculus) in which the asparagine to Walker B motif relationship is conserved.