Structures and organisation of AAA+ enhancer binding proteins in transcriptional activation.
Initiation of transcription is a major point of transcriptional regulation and invariably involves the transition from a closed to an open RNA polymerase (RNAP) promoter complex. In the case of the sigma(54)-RNAP, this multi step process requires energy, provided by ATP hydrolysis occurring within the AAA+ domain of enhancer binding proteins (EBPs). Typically, EBPs have an N-terminal regulatory domain, a central AAA+ domain that directly contacts sigma(54) and a C-terminal DNA binding domain. The following AAA+ EBP crystal structures have recently become available: heptameric AAA+ domains of NtrC1 and dimeric NtrC1 with its regulatory domain, hexameric AAA+ domains of ZraR with DNA binding domains, apo and nucleotide bound forms of the AAA+ domain of PspF as well as a cryo-EM structure of the AAA+ domain of PspF complexed with sigma(54). These AAA+ domains reveal the structural conservation between EBPs and other AAA+ domains. EBP specific structural features involved in substrate remodelling are located proximal to the pore of the hexameric ring. Parallels with the substrate binding elements near the central pore of other AAA+ members are drawn. We propose a structural model of EBPs in complex with a sigma(54)-RNAP-promoter complex.
Schumacher
Jörg
J
Division of Biology, Imperial College London, London, SW7 2AZ, UK. j.schumacher@imperial.ac.uk
Joly
Nicolas
N
Rappas
Mathieu
M
Zhang
Xiaodong
X
Buck
Martin
M
D000255:Adenosine Triphosphate / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D020134:Catalytic Domain; D016384:Consensus Sequence; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D006868:Hydrolysis; D008956:Models, Chemical; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051877:RNA Polymerase Sigma 54 / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D009711:Nucleotides; D000255:Adenosine Triphosphate; D051877:RNA Polymerase Sigma 54