A single domain of yeast poly(A)-binding protein is necessary and sufficient for RNA binding and cell viability. |
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Authors: | A B Sachs R W Davis and R D Kornberg |
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Institution: | Department of Cell Biology, Stanford University School of Medicine, California 94305. |
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Abstract: | The poly(A)-binding protein (PAB) gene of Saccharomyces cerevisiae is essential for cell growth. A 66-amino acid polypeptide containing half of a repeated N-terminal domain can replace the entire protein in vivo. Neither an octapeptide sequence conserved among eucaryotic RNA-binding proteins nor the C-terminal domain of PAB is required for function in vivo. A single N-terminal domain is nearly identical to the entire protein in the number of high-affinity sites for poly(A) binding in vitro (one site with an association constant of approximately 2 X 10(7) M-1) and in the size of the binding site (12 A residues). Multiple N-terminal domains afford a mechanism of PAB transfer between poly(A) strands. |
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