The minimal binding site (MBS) of full-length scasRap1 and scasRap1-DBD is a 12-mer (Scast12C). (A) The ability of scasRap1 versus scasRap1-DBD to bind various oligonucleotides in the EMSA is indicated with + for binding and - for no binding. The MBS is enclosed by the box. (B) EMSA with the 12-mer MBS (Scast12C). Lane 1, no protein added; lane 2, full-length scasRap1; lane 3, scasRap1-DBD. (C-D) Both full-length scasRap1 (FL) and scasRap1-DBD (DBD) can bind to a double-stranded 14 nucleotide long telomere probe (Scast14C), but can not bind to an 11-mer lacking the last 3' nucleotide of the MBS (Scast11C). (E-F) The loss of binding to a 12-mer oligonucleotide lacking one nucleotide of the MBS in the 5'-end (Scast12F), is regained by an extensive five nucleotide elongation in the 3'-end (Scast16F). Protein was added in 2-fold increasing amounts. Lanes 1 and 5, no protein added.