Electrocompetent E. coli cells (New England BioLabs #c3020K) were transformed with the EP-PCR library of GRLMR mutants. The library was subsequently transformed into T7 Express lysY (New England BioLabs #C3010I) for downstream selection experiments. To validate the mutational load of our WT-GRLMR DNA library, we picked 5 random colonies from the transformed library for sequencing. Of the randomly picked colonies, each displayed 3-9 point mutations within the ~1,400 bp gene sequence of GRLMR confirming our expected mutational load.