Structural Studies of Hmg-D-Dna Interactions

130 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2000.HMG-D is a non-sequence-specific non-histone chromosomal protein abundant in early Drosophila embryogenesis. It is a member of the HMG1/2 family of proteins, all of which share the HMG domain, a small DNA-binding structural motif. HMG1/2 proteins interact directly with nucleosomes, modulate chromatin structure, and modulate the activation of gene expression by a number of transcriptional activators. The structure of HMG-D bound to linear duplex DNA shows that the protein distorts the DNA upon binding, forming a tight protein-DNA interface. The structure of the HMG-D-DNA complex is very similar to the complexes of sequence-specific HMG-domain proteins bound to their cognate DNA molecules. However, the structure of HMG1 box A bound to a cisplatin-modified DNA molecule is very different from the nonsequence-specific and sequence-specific HMG-domain protein-DNA complexes. Analysis of the three structures of non-sequence-specific, non-enzymatic protein-DNA complexes determined to date reveals that for minor groove-binding non-sequence-specific proteins, hydrophobic interaction interfaces with base step intercalation and water-mediated hydrogen bonding are the general rule. It is proposed that this will generalize to other such proteins.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD