Structure of the DNA-binding domain of NgTRF1 reveals unique features of plant telomere-binding proteins.
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).
Ko
Sunggeon
S
Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea.
Jun
Sung-Hoon
SH
Bae
Hansol
H
Byun
Jung-Sue
JS
Han
Woong
W
Park
Heeyoung
H
Yang
Seong Wook
SW
Park
Sam-Yong
SY
Jeon
Young Ho
YH
Cheong
Chaejoon
C
Kim
Woo Taek
WT
Lee
Weontae
W
Cho
Hyun-Soo
HS
D029681:Arabidopsis Proteins / Q000737:chemistry; D001665:Binding Sites; D018360:Crystallography, X-Ray; D018744:DNA, Plant / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D040681:Structural Homology, Protein; D016615:Telomere / Q000737:chemistry* / Q000378:metabolism; D035321:Telomeric Repeat Binding Protein 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics
D029681:Arabidopsis Proteins; D018744:DNA, Plant; D010940:Plant Proteins; D035321:Telomeric Repeat Binding Protein 1