%0 Journal Article
%A Lentzen, Georg
%A Dobberstein, Bernhard
%A Wintermeyer, Wolfgang
%D 1994
%F heidok:8302
%J FEBS Letters
%P 233-238
%R 10.11588/heidok.00008302
%T Formation of SRP-like particle induces a conformational change in E. coli 4.5S RNA
%U https://archiv.ub.uni-heidelberg.de/volltextserver/8302/
%V 348
%X E. coli P48 protein is homologous to the SRP54 component of the eukaryotic signal recognition particle. In vivo, P48 is associated with 4.5S RNA which shares a homology with eukaryotic SRP RNA. To study the interaction between P48 and 4.5S RNA in vitro, we used 4.5S RNA with fluorescein coupled to the 3'-terminal ribose. Upon binding of P48, the fluorescent 4.5S RNA shows a substantial decrease in fluorescence. Fluorescence quenching as well as anisotropy measurements reveal that the effect is not due to a direct interaction of P48 with the dye. This suggests that the binding of P48 induces a conformational change in 4.5S RNA which affects the structure at the 3' end of the RNA. From equilibrium titrations with fluorescent 4.5S RNA, a dissociation constant of 0.15 microns is obtained for the RNA.protein complex. The formation of the complex is not affected by GTP binding to or hydrolysis by P48.