Exchange of Histidine Spacing between Spl and GLI Zinc Fingers:Distinct Effect of Histidine Spacing-Linker Region on DNA Binding

摘要

In the DNA recognition mode of C2H2-type zinc fingers,the finger-finger connection region,consisting of the histidine spacing (HX_(3-5)H) and linker,would be important for determining the orientation of the zinc finger domains.To clarify the influence of spacing between two ligand histidines in the DNA binding,we exchanged the histidine spacing between Spl and GLI zinc fingers,which have an HX_3H-TGEKK linker (typical) and an HX4H-SNEKP linker (atypical),respectively.A significant decrease in the DNA binding affinity and specificity is found in Spl-type peptides,whereas GLI-type peptides show a mild reduction.To evaluate the effect of the linker characteristics,we further designed Spl-type mutants with an SNEKP linker.As a result,the significant effect of the histidine spacing in Spl-type peptides was reduced.These results demonstrate that (1) the histidine spacing significantly affects the DNA binding of zinc finger proteins and (2) the histidine spacing and the following linker regions are one effective target for regulating the DNA recognition mode of zinc finger proteins.