RNA recognition by the Vts1p SAM domain

The putative yeast post-transcriptional regulator Vts1p and its related protein Smaug, from Drosophila melanogaster, each use a sterile alpha motif (SAM) domain to bind an RNA hairpin termed the Smaug recognition element (SRE). Here, we present the NMR structures of the Vts1p - SRE complex and the free SRE. Structural highlights include the direct recognition of a guanine base and the formation or stabilization of a base pair in the SRE loop.