Fig. 1

A multiple-sequence alignment of PheS from a variety of distantly related species. Full length sequences of PheS were determined using Clustal X. The secondary structure of PheS in E. coli (PDB code: 3PCO) is shown at the top of each set of sequence. The conserved alanine residues mutated to generate p-Cl-Phe sensitivity were boxed with a thick line and indicated with a pentagram. α α-helix, β β-sheet, π π-helix, η 3₁₀-helix, TT β-turn