Related Experiment Video
Updated: Jun 20, 2026

Investigating Interactions Between Histone Modifying Enzymes and Transcription Factors in vivo by Fluorescence Resonance Energy Transfer
Published on: October 14, 2022
POT1 proteins in green algae and land plants: DNA-binding properties and evidence of co-evolution with telomeric DNA
Eugene V Shakirov1, Xiangyu Song, Jessica A Joseph
1Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA.
Abstract:
Telomeric DNA terminates with a single-stranded 3' G-overhang that in vertebrates and fission yeast is bound by POT1 (Protection Of Telomeres). However, no in vitro telomeric DNA binding is associated with Arabidopsis POT1 paralogs. To further investigate POT1-DNA interaction in plants, we cloned POT1 genes from 11 plant species representing major branches of plant kingdom. Telomeric DNA binding was associated with POT1 proteins from the green alga Ostreococcus lucimarinus and two flowering plants, maize and Asparagus. Site-directed mutagenesis revealed that several residues critical for telomeric DNA recognition in vertebrates are functionally conserved in plant POT1 proteins. However, the plant proteins varied in their minimal DNA-binding sites and nucleotide recognition properties. Green alga POT1 exhibited a strong preference for the canonical plant telomere repeat sequence TTTAGGG with no detectable binding to hexanucleotide telomere repeat TTAGGG found in vertebrates and some plants, including Asparagus. In contrast, POT1 proteins from maize and Asparagus bound TTAGGG repeats with only slightly reduced affinity relative to the TTTAGGG sequence. We conclude that the nucleic acid binding site in plant POT1 proteins is evolving rapidly, and that the recent acquisition of TTAGGG telomere repeats in Asparagus appears to have co-evolved with changes in POT1 DNA sequence recognition.
Related Concept Videos
Green Algae
Conserved Binding Sites
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally analyses the...
The Anatomy of Chloroplasts
Structure of Chloroplasts
A...
Protein Transport to the Inner Chloroplast Membrane
Red Algae
Overview of Algae
