An MIT team has discovered the most complicated knot ever seen in a protein, and they believe it may be linked to the protein's function as a rescue agent for proteins marked for destruction.
The protein human ubiquitin hydrolase was discovered to have the most complicated knot ever observed and the simplified diagram above shows how the protein crosses itself five times. Another protein called ubiquitin delivers a "kiss of death" to other proteins in a cell marking them for destruction. It is the protein seen (schematically) above that carries out rescue work. The researchers believe that proteins with complex knots may be more difficult to suck into the protease as it works and further makes the unfolding of the protein difficult which is necessary for degradation. Some over complication of knots through mutation may also be link to Parkinson and cancer.