Position of Gifsy-1 Xis mutants relative to Robetta secondary structure prediction. Red rectangles indicate sequences with a propensity to form α-helixes. Yellow arrows indicate sequences with a propensity to form β-strands. The positions and identities of random mutations generated in the protein are indicated above the primary amino acid sequence. Red characters indicate mutants generated through mutagenic PCR. Black characters indicate mutations generated through DES mutagenesis.