Structure of the DNA-binding domain of NgTRF1 reveals unique features of plant telomere-binding proteins.

Abstract

Telomeres are protein-DNA elements that are located at the ends of linear eukaryotic chromosomes. In concert with various telomere-binding proteins, they play an essential role in genome stability. We determined the structure of the DNA-binding domain of NgTRF1, a double-stranded telomere-binding protein of tobacco, using multidimensional NMR spectroscopy and X-ray crystallography. The DNA-binding domain of NgTRF1 contained the Myb-like domain and C-terminal Myb-extension that is characteristic of plant double-stranded telomere-binding proteins. It encompassed amino acids 561-681 (NgTRF1(561-681)), and was composed of 4 alpha-helices. We also determined the structure of NgTRF1(561-681) bound to plant telomeric DNA. We identified several amino acid residues that interacted directly with DNA, and confirmed their role in the binding of NgTRF1 to telomere using site-directed mutagenesis. Based on a structural comparison of the DNA-binding domains of NgTRF1 and human TRF1 (hTRF1), NgTRF1 has both common and unique DNA-binding properties. Interaction of Myb-like domain with telomeric sequences is almost identical in NgTRF1(561-681) with the DNA-binding domain of hTRF1. The interaction of Arg-638 with the telomeric DNA, which is unique in NgTRF1(561-681), may provide the structural explanation for the specificity of NgTRF1 to the plant telomere sequences, (TTTAGGG)(n).

• Authors: Sunggeon Ko, Sung-Hoon Jun, Hansol Bae, Jung-Sue Byun, Woong Han, Heeyoung Park, Seong Wook Yang, Sam-Yong Park, Young Ho Jeon, Chaejoon Cheong, Woo Taek Kim, Weontae Lee, Hyun-Soo Cho
• Journal: Nucleic acids research (Nucleic Acids Res) Vol. 36 Issue 8 Pg. 2739-55 (May 2008) ISSN: 1362-4962 [Electronic] England
• PMID: 18367475 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Arabidopsis Proteins
• DNA, Plant
• Plant Proteins
• Telomeric Repeat Binding Protein 1

Topics

• Arabidopsis Proteins (chemistry)
• Binding Sites
• Crystallography, X-Ray
• DNA, Plant (chemistry, metabolism)
• Humans
• Models, Molecular
• Mutagenesis, Site-Directed
• Nuclear Magnetic Resonance, Biomolecular
• Plant Proteins (chemistry, genetics, metabolism)
• Protein Structure, Tertiary
• Structural Homology, Protein
• Telomere (chemistry, metabolism)
• Telomeric Repeat Binding Protein 1 (chemistry, genetics, metabolism)
• Tobacco (genetics)