Structure and function of unidecapeptide in the poly(A) binding protein

We have shown that a synthetic unidecapeptide bound to poly(A) stimulated mRNA (poly A)+ [Rubin & Halim (1993), Biochemistry and Mol. Biol. Int. 31,267-278]. We further examined the structure of the unidecapeptide by circular dichroism spectroscopy and found it to be beta-sheet. Furthermore, the synthetic peptide was found to shorten and lengthen the poly(A) tail at the 3' end of rabbit globin mRNA. The shortening of the poly(A) tail was caused by a hexamer [K (or R)GFGFV], while the lengthening of the poly(A) tail was stimulated by the GKS sequence.