SUNY at Albany
June 19-23, 2001
Structure and RNA Recognition In The RRM and dsRBD Protein Families
We are dissecting the structural principles underlying RNA-protein recognition in two classes of RNA-binding proteins, the RRM and the double-stranded RNA binding domain (dsRBD). We have related the structural information and the RNA recognition mechanisms to the function of human U1A and Drosophila Staufen proteins during regulation of mRNA 3Õ-end formation and localization. The structure of the RNA complex of Staufen dsRBD3 has shown how dsRBD proteins bind dsRNA and revealed phylogenetically conserved surfaces in different dsRBD domains of Staufen with distinct functions during mRNA localization. The phylogenetic analysis of domains across Staufen proteins from different organism an across different members of the dsRBD family have revealed conserved features of the RNA recognition surface that provide the protein family with its generic ability to bind double stranded RNA regardless of its sequence. Other domain-specific features identified in our structural analysis may provide the ability to discriminate between different RNAs. The investigation of another member of the dsRBD family, the yeast RNA processing enzyme Rnt1, has revealed new features of the protein structure and provided further insight into how discrimination is achieved. In addition to the structural investigation, we have measured motional properties of the protein-RNA interfaces by recording dynamics of both the backbone and methylated side chains in each protein and protein-RNA complex. These data reveal a complex set of dynamic processes, with some sites on the interface retaining significant conformational flexibility while others are more rigid. The dynamic properties of the interface strongly correlate with the importance of different sites in determining specificity of recognition.
Gabriele Varani, Paul Cole, Nicolas Leulliot, Andres Ramos and Luca Varani
MRC Laboratory of Molecular Biology Hills Road - Cambridge CB2 2QH - UK England