Swi2/Snf2 remodelers: hybrid views on hybrid molecular machines

Swi2/Snf2 (switch/sucrose non-fermentable) enzymes form a large and diverse class of proteins and multiprotein assemblies that remodel nucleic acid:protein complexes, using the energy of ATP hydrolysis. The core Swi2/Snf2 type ATPase domain belongs to the ‘helicase and NTP driven nucleic acid translocase’ superfamily 2 (SF2). It serves as a motor that functionally and structurally interacts with different targeting domains and functional modules to drive a plethora of remodeling activities in chromatin structure and dynamics, transcription regulation and DNA repair. Recent progress on the interaction of Swi2/Snf2 enzymes and multiprotein assemblies with their substrate nucleic acids and proteins, using hybrid structural biology methods, illuminates mechanisms for complex chemo-mechanical remodeling reactions. For Mot1, a hybrid mechanism of remodeler and chaperone emerged.

► Swi2/Snf2 proteins/multiprotein assemblies remodel nucleic acid: protein complexes.
► Core Swi2/Snf2 ATPase domain is a structurally and functionally versatile motor.
► Hybrid methods pave the way toward nucleosome:remodeler structures and mechanisms.
► The remodelers Mot1, Chd1 and Isw1 use different ATP-driven multistep mechanisms.
► Mot1 employs a hybrid mechanism of remodeler and chaperone.