FIGURE 5.

Comparison of the primary and secondary structures of CtFabI and SaFabI. The primary and overall secondary structures of CtFabI and SaFabI are conserved. The two substrate binding loop regions are surrounded by boxes with colors corresponding to the structural elements depicted in Fig. 6. Notably, the helical loop η3 in SaFabI that contains the critical Met-99 residue is replaced in CtFabI with a less structured loop region containing a two-residue deletion. Red, identical residues. Structure-based sequence alignments were performed using Salign (47) and analyzed using ESPript3 (48).