Transient HMGB protein interactions with B-DNA duplexes and complexes.
HMGB proteins are abundant, non-histone proteins in eukaryotic chromatin. HMGB proteins contain one or two conserved "HMG boxes" and can be sequence-specific or nonspecific in their DNA binding. HMGB proteins cause strong DNA bending and bind preferentially to deformed DNAs. We wish to understand how HMGB proteins increase the apparent flexibility of non-distorted B-form DNA. We test the hypothesis that HMGB proteins bind transiently, creating an ensemble of distorted DNAs with rapidly interconverting conformations. We show that binding of B-form DNA by HMGB proteins is both weak and transient under conditions where DNA cyclization is strongly enhanced. We also detect novel complexes in which HMGB proteins simultaneously bind more than one DNA duplex.
Zimmerman
Jeff
J
Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
Maher
L James
LJ
D000595:Amino Acid Sequence; D004247:DNA / Q000737:chemistry*; D024243:HMGB1 Protein / Q000737:chemistry* / Q000235:genetics; D024261:HMGB2 Protein / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary
D024243:HMGB1 Protein; D024261:HMGB2 Protein; D004247:DNA