double-stranded telomeric DNA binding

Definition

Target type: molecularfunction

Binding to double-stranded telomere-associated DNA. [GOC:jl, ISBN:0321000382]

Double-stranded telomeric DNA binding is a crucial molecular function that plays a vital role in maintaining the integrity and stability of chromosomes. Telomeres are specialized structures at the ends of chromosomes that protect them from degradation and fusion. They consist of repetitive DNA sequences, typically rich in guanine and thymine bases (G-rich repeats), and associated proteins.

Double-stranded telomeric DNA binding proteins, such as TRF1 and TRF2 in humans, recognize and bind to the double-stranded telomeric DNA. This binding is highly specific and involves interactions with the G-rich repeats through a variety of mechanisms, including:

* **Base stacking:** The proteins stack their aromatic amino acids (tryptophan, phenylalanine, tyrosine) against the guanine bases of the telomeric DNA. This stacking interaction stabilizes the protein-DNA complex and contributes to the specificity of the binding.
* **Hydrogen bonding:** The protein residues form hydrogen bonds with the DNA bases, further enhancing the stability of the interaction.
* **Electrostatic interactions:** The protein’s positively charged residues interact with the negatively charged phosphate backbone of the DNA.

The binding of these proteins to the telomeric DNA is crucial for various functions, including:

* **Protection of chromosome ends:** The binding of proteins to the telomeres prevents the ends of chromosomes from being recognized as double-stranded breaks, which can lead to DNA degradation and chromosome fusion.
* **Regulation of telomere length:** Telomeric DNA is shortened with each round of DNA replication, and these proteins play a role in controlling the rate of telomere shortening.
* **Formation of the telomeric loop (T-loop):** TRF2 promotes the formation of a T-loop, a protective structure that hides the 3' overhang of the telomere. This structure further contributes to the stability of the telomere and prevents degradation.
* **Recruitment of other proteins:** These proteins can act as platforms for recruiting other proteins involved in telomere maintenance, including those involved in DNA replication, repair, and recombination.

Overall, the double-stranded telomeric DNA binding function is essential for the proper maintenance and stability of chromosomes. It is a highly regulated process involving specific protein-DNA interactions that ensure the integrity of the genome and prevent genomic instability.'
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Proteins (1)

Compounds (17)