Spatial structure of N-terminal multimerization domain from Drosophila melanogaster CTCF insulator protein was studied using circular dichroism and small-angle X-ray scattering (SAXS). This domain has no significant homology in amino acid sequence with any other known protein domain. Circular dichroism spectra revealed that N- terminal domain of Drosophila CTCF protein almost completely lacks secondary structure. SAXS data indicated that domain possess a stable compact conformation in solution and exists as a tetramer. Low-resolution models of spatial structure of the tetramer were built. Tetramer formation is also supported by dynamic light scattering (DLS) and size-exclusion chromatography.
multimerization, small-angle X-ray scattering, circular dichroism, chromatin
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