Insights into the dynamics of specific telomeric single-stranded DNA recognition by Pot1pN.
The N-terminal oligonucleotide/oligosaccharide-binding fold domain of the Schizosaccharomyces pombe protection of telomeres 1 (Pot1) protein, Pot1pN (residues 1-187 of full-length Pot1), specifically recognizes telomeric single-stranded DNA (ssDNA) via a complex series of molecular interactions that are punctuated by unusual internucleotide hydrogen bonds. While the structure of ssDNA-bound Pot1pN provides an initial model for understanding how the Pot1pN-ssDNA complex is assembled and how specific nucleotide recognition occurs, further refinement requires knowledge of the ssDNA-free state of Pot1pN and the dynamic changes that accompany the binding of ssDNA. Using NMR strategies, we found that ssDNA-free Pot1pN adopts a similar overall protein backbone topology as ssDNA-bound Pot1pN does. Although the backbone structure remained relatively unchanged, we observed unexpected differential dynamic changes within the ssDNA-binding pockets of Pot1pN upon binding of cognate ssDNA. These studies support a model in which conformational selection and induced fit play important roles in the recognition of ssDNA by Pot1pN. Furthermore, the studies presented here provide a more comprehensive understanding of how specific nucleotide recognition is achieved by the telomere-end protection family of essential proteins.
Croy
Johnny E
JE
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA.
Wuttke
Deborah S
DS
D001665:Binding Sites; D018360:Crystallography, X-Ray; D004271:DNA, Fungal / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000378:metabolism*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D009838:Oligodeoxyribonucleotides / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000089804:Shelterin Complex; D013053:Spectrophotometry; D016615:Telomere / Q000378:metabolism*; D034501:Telomere-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013816:Thermodynamics
D004271:DNA, Fungal; D004277:DNA, Single-Stranded; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins; C499082:pot1 protein, S pombe