Turning selfish proteins into programmable genome editors (733.2)

Abstract

Though no suitable methods for genome editing yet exist, the most promising approaches utilize targeted nucleases and take advantage of a cell’s natural repair processes that either disrupts the cleaved sequence or repairs it using a donor DNA template. LAGLIDADG Homing Endonucleases (LHE’s) are naturally occurring selfish proteins with two key features ideal for genome editing: recognition of a long DNA target site (~22 bp) and double‐stranded cleaving activity. Originally thought to be impossible to engineer due to their size and complexity, recent approaches based on experimentally determined structural models to direct the bioengineering process have proven successful. The aim of my research project was to solve the three dimensional structures of various LHE’s using x‐ray crystallography. Using E. coli‐expressed proteins, I solved the structures of two LHE’s (I‐GpeMI and I‐CpaMI) bound to their target DNA. With these structures we are able to identify DNA‐interacting amino acids and focus our engineering efforts of the enzyme scaffolds towards new DNA target sites.Grant Funding Source: Murdock Trust