Divalent Metal- and High Mobility Group N Protein-Dependent Nucleosome Stability and Conformation

Figure 4

Thermal denaturation assays reveal influence of divalent metal and HMGNs on nucleosome stability. ((a)–(h)) Sample buffer was near physiological ionic strength without divalent metal ((a)–(d); 1XTB, default) or with 1 mM Mg²⁺ or Ca²⁺ ((a)–(c), (e)–(h); +Mg, +Ca). Assays were conducted on naked NCP DNA fragments alone (a), NCP ((b), (c)), NCP-601 with 3 : 1 HMGN : NCP stoichiometry in the absence of divalent metal (d), NCP-601 with 1 : 1 (e), 2 : 1 (f), or 3 : 1 (g) HMGN : NCP stoichiometry and NCP147 with 2 : 1 HMGN : NCP stoichiometry (h). ((d)–(h)) “NCP” corresponds to an HMGN-free control sample.