Figure 2.

Schematic of stopped-flow mixing experiment to probe salt-induced disassembly of NCPs without sucrose. Compact NCPs in 0.2 M NaCl mix with buffer containing 3.0 M NaCl to achieve a final NaCl concentration of 1.9 M, where full NCP disassembly occurs. The optimal flow rates and volumes used were 6 ml/s and 315 μl for 0% sucrose and 7.5 ml/s and 375 μl for 50% sucrose. In 0% sucrose, both nucleosomal DNA and histones are ‘visible’, hence TR-SAXS data reports changes in NCP global size, structure and composition. In 50% sucrose, only nucleosomal DNA is ‘visible’, TR-SAXS data directly reveals changes in DNA conformation. λ is the wavelength of the incident X-rays (in Å).