High-fidelity de novo DNA synthesis using enzymes
The Promise of enzymatic DNA Synthesis
Over billions of years of evolution, nature has developed enzymes that have superb characteristics for synthesizing DNA. Harnessing these enzymes for manufacturing DNA will enable a synthesis procedure that promises to be:
- Faster, eliminating the bottleneck of DNA synthesis for the test/build/learn cycle of biological research
- More precise, because mild conditions will prevent side reactions, enabling synthesis of longer sequences.
- Sustainable, requiring neither organic solvents nor toxic reagents. This will enable the development of convenient and user-friendly DNA synthesis devices for laboratories.
writing dna using a polymerase
Soon after the discovery of "polymerase" enzymes that rapidly copy DNA with exquisite fidelity, scientists have dreamed of harnessing a polymerase to "write" desired sequences. One special polymerase, Terminal Deoxynucleotidyl Transferase (TdT), has been considered the prime candidate for this purpose because, unlike all other polymerases that copy an existing sequence, TdT creates random DNA. In order to harness TdT for the synthesis of a desired sequence, its activity must be controlled so that it adds a single base to a DNA molecule and then stops, so the desired sequence can be synthesized step-by-step. Proposals to employ TdT for the stepwise synthesis of desired sequences date back to the early 1960s. However, controlling TdT's additions while maintaining its fast incorporation kinetics has proven to be difficult. We are developing a new a technique to control additions of a polymerase that will finally unlock the potential TdT for de novo DNA synthesis.