Figure 5.

A kinetic scheme showing different steps in the Rho-recruitment process. OH and CH denote the ‘open’ and ‘close’ hexamer states of Rho as described in the two crystal structures (25,26). It is likely that the major isomerization step as well as the rate-limiting step involves the OH to CH conversion, which is induced by threading of the RNA into the SBS and by the binding of ATP. Rho translocation events denoted as ‘→→→’ are accompanied by sequential ATP hydrolysis steps. The rate constants defining the binding steps are also indicated. Proposed involvement of NusG at the isomerization step is shown.