RAP1 a Telomerase Binding Protein in Yeast.

3D Model

RAP1 (repressor activator protein 1) is a large (827 amino acid) non-histone DNA binding protein. RAP1 improves the telomeric stability in yeast by binding almost continuously along telomeric DNA. RAP1 also behaves as a transcription factor where it can act as a repressor or activator of transcription depending on its context. Binding sites for RAP1 are found in a range of promoters. The primary function of RAP1 is to bind to DNA in a sequence specific manner. This allows RAP1 to stabilise the double stranded telomeres of yeast and function as a transcription factor. There are two structurally similar domains in RAP1 (shown in lilac and pale green in the 3D rendering) these domains bind in a sequence specific fashion to tandem repeats of the DNA sequence. The DNA in this diagram is pictured in white.

This tour explores the sequence specific binding of the DNA binding domain of RAP1 from the N terminus to the C terminus, demonstrating how RAP1 achieves its sequence specificity.