This provision can be made by installing an extra depth of structural base at the defined access points. (educationbusinessuk.net)
Chang, Y.; Zhang, X.; Horton, J. R.; Upadhyay, A. K.; Spannhoff, A.; Liu, J.; Snyder, J. P.; Bedford, M. T.; Cheng, X. Structural basis for G9a - like protein lysine methyltransferase inhibition by BIX - 01294. (thesgc.org)
«It's the packing density that could change and limit the accessibility of chromatin, providing a local and global structural basis through which different combinations of DNA sequences, nucleosome variations and modifications could be integrated in the nucleus to exquisitely fine - tune the functional activity and accessibility of our genomes.» (sciencedaily.com)