# Haddock model without knowing the binding interface **URL:** \ **Category:** HADDOCK\ **Created:** [August 2, 2021, 5:10pm UTC](https://ask.bioexcel.eu/t/haddock-model-without-knowing-the-binding-interface/3190 "2021-08-02T17:10:54Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![binbinwang](https://avatars.discourse-cdn.com/v4/letter/b/b5ac83/32.png) [@binbinwang](https://ask.bioexcel.eu/u/binbinwang)\ **Post date:** [August 2, 2021, 5:10pm UTC](https://ask.bioexcel.eu/t/haddock-model-without-knowing-the-binding-interface/3190/1 "2021-08-02T17:10:55Z")
Hello All, For the protein complex (protein A-protein B), I know the residues of protein A involved in the interactions with protein B, but I have no clue of the binding area for protein B. Is it possible to apply haddock to get the complex structure model? If it is possible, how can I define the ambiguous distance restraints between protein A and protein B for the docking? Thank you very much! ---
**Author:** ![amjjbonvin](https://dub1.discourse-cdn.com/flex013/user_avatar/ask.bioexcel.eu/amjjbonvin/32/23_2.png) [@amjjbonvin](https://ask.bioexcel.eu/u/amjjbonvin)\ **Post date:** [August 2, 2021, 5:58pm UTC](https://ask.bioexcel.eu/t/haddock-model-without-knowing-the-binding-interface/3190/2 "2021-08-02T17:58:33Z")
You can try the following: 1. Define the active residues on protein A (the ones involved in the interaction) 2. Define the entire surface of protein B as passive (there is an option on the 2.4 web portal to do that automatically 3. Increase the sampling to say 10000/400/400 models for the three stages of HADDOCK ---
**Author:** ![binbinwang](https://avatars.discourse-cdn.com/v4/letter/b/b5ac83/32.png) [@binbinwang](https://ask.bioexcel.eu/u/binbinwang)\ **Post date:** [August 2, 2021, 6:19pm UTC](https://ask.bioexcel.eu/t/haddock-model-without-knowing-the-binding-interface/3190/3 "2021-08-02T18:19:09Z")
Thanks a lot, Bin