This post is in continuation to the previous post Telomeres: The ends of the chromosome
Once telomeres have been added to the chromosome ends, different organisms use any of the three different methods to protect the ends of chromosomes.
1) The ends of telomeres which are guanine-rich form complex structures called the G-tetraplex. Four Gs form this planar structure in which they are hydrogen bonded to each other.
2) Some proteins are found to bind to the 3′ ends of telomeres. In the ciliate oxytricha nova, a protein called the telomere-end binding protein (TEBP) attaches to the 3′ ends of telomeres and protects them.
3) A third structure known as t-loop has been discovered at the end of mammalian telomeres. This loop forms at chromosomes ends under the influence of a protein called TRF2 (telomere repeat-binding factor), which causes the 3′ end of the chromosome to loop around and interdigitate into the double helix, forming the loop.