Binding of the C-terminal domain of L11 stabilizes the tertiary structure of a compactly folded RNA domain whereas the N-terminus is implicated in the binding to the antibiotic thiostrepton (Xing and Draper, 1996). The conformation of the RNA-L11-complex is structurally well characterized (Wimberly et al., 1999, Conn et al., 1999). In addition, the conformation of the C-terminal domain of L11 from Bacillus stearothermophilus has been characterized in its RNA bound and free form by NMR (Hinck et al., 1997, Markus et al., 1997). Yet, to obtain a more detailed picture of the dynamic processes accompanying RNA-protein interactions we characterize in detail the conformation and the dynamics of the full-length protein free in solution. In particular, the relative orientation of the N- and C-terminal domain of the protein in its free form is being investigated by NMR-spectroscopy. By analysis of long-range structural information derived from heteronuclear relaxation rates and residual dipolar couplings, it can be shown that the two domains are connected by a relatively rigid poly-Proline helix, their relative flexibility is low and the prominent conformation in solution preorganizes the correct conformation in complex with RNA.