Expression, Purification, and ATP Hydrolysis Activity Measurement of <i>Ct</i> ISWI and <i>Ct</i> ATPase

Chromatin remodeling is a process of regulating gene expression levels by altering chromatin structure, facilitated by chromatin remodeling factors. ISWI (Imitation SWItch), a type of chromatin remodeling factor, plays a crucial role in epigenetic regulatory processes, such as cell differentiation and development. It primarily achieves remodeling effects by promoting the direct sliding of nucleosomes and their relocation on DNA. To study the function and structural characteristics of ISWI, this basic protocol describes a simple and rapid procedure for the large-scale expression and purification of soluble CtISWI_77-1038 and CtATPase_77-722 proteins in Escherichia coli (E. coli). The procedure provides high yields (∼20 mg) and is followed by in vitro measurement of ATP hydrolysis activity. © 2025 Wiley Periodicals LLC. Basic Protocol: Expression, purification, and ATP hydrolysis activity measurement of CtISWI and CtATPase.