An effective approach for generating a three-Cys2His2 zinc-finger-DNA complex model by docking

Area of Science:

• Structural Biology
• Computational Biology
• Biochemistry

Background:

• Determining protein-DNA complex structures via NMR and X-ray crystallography is often challenging.
• High Ambiguity-Driven DOCKing (HADDOCK) is a computational tool for modeling protein-DNA complexes, but modeling proteins wrapping around DNA has not been reported.
• Accurate modeling requires defining specific ambiguous interaction restraints (AIRs) for Cys2His2 zinc-finger proteins due to complex binding geometry.

Purpose of the Study:

• To develop and validate a computational approach for modeling protein-DNA complexes where the protein wraps around DNA.
• To investigate the effect of geometric distribution of AIRs on docking accuracy for zinc-finger protein-DNA complexes.
• To generate a novel Sp1-DNA complex model using the established approach.

Main Methods:

• Generated Zif268-DNA complex models using three distinct sets of AIRs to assess geometric distribution effects.
• Derived a modeling strategy for three-Cys2His2 zinc-finger protein-DNA complexes based on docking studies and existing crystal structures.
• Applied the derived approach to calculate an Sp1-DNA complex model.

Main Results:

• Models generated with two AIRs exhibiting good geometric distribution showed favorable results in terms of wrap-around conformation, interface accuracy, and native contact fractions.
• A robust modeling approach for three-Cys2His2 zinc-finger protein-DNA complexes was established.
• The calculated Sp1-DNA complex model demonstrated good agreement with previously reported interactions.

Conclusions:

• Two AIRs with appropriate geometric distribution in each zinc-finger domain are sufficient for accurate modeling of protein-DNA complexes with a wrap-around conformation.
• This computational approach is efficient for modeling unknown zinc-finger protein-DNA complex structures where the protein wraps around DNA.
• A detailed flowchart outlining the modeling procedure is provided.