FIG. 5.

Chromosomally encoded yeast protein Shf1p that interacts with the STB locus. The monohybrid assay identified the STB-interacting host protein as the product of the YIL036W locus (from the yeast genome bank; now designated as SHF1). The complete nucleotide sequence of the genetically and biochemically uncharacterized SHF1 gene, along with the amino acid sequence of the presumed protein product encoded by it, are shown. The rectangular box (from Phe-377 to Ser-294) indicates a potential GTP or ATP binding sequence (prediction by the UCLA-DOE structure prediction server). The shaded box (from Trp-421 to Phe-454) is highly homologous to the consensus CREB motif present in the ATF/bZIP family of transcriptional regulatory proteins. (For a comparison of this region to homologous regions in a selected set of eukaryotic CREB/bZIP proteins, see Fig. 6.) The abundance of glutamine residues in the hatched box (Gln-118 to Gln-135) is suggestive of the activation patches in a number of transcription factors (6, 7).