Site-Specific and Trigger-Activated Modification of Proteins by Means of Catalytic Hemin/G-quadruplex (hGQ) DNAzyme Nanostructures

Synthetic DNA that forms various G-quadruplex nanostructures, in combination with hemin, N -methyl luminol derivatives, and H2O2 can site-specifically modify proteins (i.e. evidence is provided for lysozyme and human alpha-thrombin). The catalytic modification is completed in 15-30 mins, and the site-specificity is influenced by the G-quadruplex topology (a total of 22 G-quadruplex forming sequences was tested). We also show that the heavy chain of the therapeutic antibody trastuzumab is modified, which facilitates the preparation of antibody-drug conjugates. Furthermore, a trigger can be programmed into this synthetic DNA so that the protein modification chemistry is made dependent on an external trigger. Techniques used: HPLC, SDS-PAGE, LC-MS/MS, NMR.