Article

She2p Is a Novel RNA Binding Protein with a Basic Helical Hairpin Motif

Laboratories of Molecular Biophysics and The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
Cell (Impact Factor: 33.12). 11/2004; 119(4):491-502. DOI: 10.1016/j.cell.2004.10.018
Source: PubMed

ABSTRACT Selective transport of mRNAs in ribonucleoprotein particles (mRNP) ensures asymmetric distribution of information within and among eukaryotic cells. Actin-dependent transport of ASH1 mRNA in yeast represents one of the best-characterized examples of mRNP translocation. Formation of the ASH1 mRNP requires recognition of zip code elements by the RNA binding protein She2p. We determined the X-ray structure of She2p at 1.95 A resolution. She2p is a member of a previously unknown class of nucleic acid binding proteins, composed of a single globular domain with a five alpha helix bundle that forms a symmetric homodimer. After demonstrating potent, dimer-dependent RNA binding in vitro, we mapped the RNA binding surface of She2p to a basic helical hairpin in vitro and in vivo and present a mechanism for mRNA-dependent initiation of ASH1 mRNP complex assembly.

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