Proposed DNA-binding modes of ZPTs. (A) Two types of ZPT–DNA interactions. In Type-I binding (left), the linker wraps around the major groove. In Type-II binding (right), the linker traverses the minor groove. (B) DNA-binding models of ZPT2-14 in different spacing contexts. In 10-base spacing context (5′-AGT-N₁₀-AGT-3′), two ZFs bind to AGTs on either strand presumably by Type-II mode (a)–(c). In 5-base spacing context, ZPT2-14 binds to 5′-AGT-N₅-AGT-3′  in Type I mode (d). It also binds to 5′-ACT-N₅-AGT-3′ in antiparallel Type II mode at high affinity (e). Binding to 5′-ACT-N₅-AGT-3′ is at low affinity (f).