title: An altered DNA conformation in origin region I is a determinant for the binding of SV40 large T antigen.
abstract: Seventeen base pairs of DNA from SV40 origin region I encode a tripartite binding site for a dimeric mass of SV40 large T antigen. Two binding components are the directly repeated pentanucleotide sequences 5'-GAGGC-3'/5'-GCCTC-3'. The third component is the asymmetric sequence 5'-TTTTTTG-3'/5'-CAAAAAA-3' that separates the pentanucleotides. Nucleotide-specific features of this spacer element stabilize binding to the adjacent pentanucleotides. We report here that the spacer sequence determines a DNA conformation that correlates with high affinity binding of T antigen. The nature of the spacer sequence suggests that the DNA is bent. We propose that binding of T antigen to region I proceeds through monomer-pentanucleotide interactions and either protein-protein or protein-spacer interactions directed by the spacer-encoded structure.
mesh_terms: D000957:Antigens, Viral, Tumor; D001483:Base Sequence; D004261:DNA Replication; D004279:DNA, Viral / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D009690:Nucleic Acid Conformation; D009698:Nucleoproteins / Q000032:analysis; D013539:Simian virus 40 / Q000235:genetics*; D013329:Structure-Activity Relationship; D014779:Virus Replication
chemical_list: D000957:Antigens, Viral, Tumor; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D009698:Nucleoproteins