TABLE 1.

Mutants that were designed in both the Topo-44 and Topo-78 fragments

The first column lists the six residues involved in the present study, the second column lists all of the mutations that were designed for each of the active site residues, and the third and fourth columns list the mutants that were successfully purified and assayed in the Topo-44 and Topo-78 backbones, respectively.

Residue	Designed mutations	Purified in Topo-44 backbone	Purified in Topo-78 backbone
Arginine 131	Ala, Lys, Gln	Ala, Lys	Ala, Gln
Arginine 144	Ala, Lys, Gln		Ala
Histidine 200	Ala, Arg, Asn, Gln, Glu	Ala, Arg, Asn, Gln, Glu	Ala, Arg, Asn, Glu
Glutamate 215	Ala, His, Leu, Gln, Arg	Ala, His, Gln, Arg	Ala, His, Leu, Gln
Lysine 218	Ala, Glu, Gln, Arg	Arg	Ala, Glu, Gln, Arg
Tyrosine 226	Phe	Phe	Phe