Nucleotide-induced asymmetry within ATPase activator ring drives σ54-RNAP interaction and ATP hydrolysis.

ABSTRACT: It is largely unknown how the typical homomeric ring geometry of ATPases associated with various cellular activities enables them to perform mechanical work. Small-angle solution X-ray scattering, crystallography, and electron microscopy (EM) reconstructions revealed that partial ATP occupancy caused the heptameric closed ring of the bacterial enhancer-binding protein (bEBP) NtrC1 to rearrange into a hexameric split ring of striking asymmetry. The highly conserved and functionally crucial GAFTGA loops responsible for interacting with σ54-RNA polymerase formed a spiral staircase. We propose that splitting of the ensemble directs ATP hydrolysis within the oligomer, and the ring's asymmetry guides interaction between ATPase and the complex of σ54 and promoter DNA. Similarity between the struc

SUBMITTER: Sysoeva TA 

PROVIDER: S-EPMC3841738 | biostudies-literature | 2013 Nov

REPOSITORIES: biostudies-literature