FIG 4.

Tyrosine 57 is important for hemin affinity to Cj1386. (A) Absorption spectra of 10 μM Cj1386^WT and 10 μM Cj1386^Y57A in 100 mM NaCl, 20 mM Tris, pH 7.4. (B) Absorption spectra of 10 μM Cj1386^Y57A and 10 μM Cj1386^Y57A plus 10 μM hemin in 100 mM NaCl, 20 mM Tris, pH 7.4. (C) Growth inhibition analysis of wild-type C. jejuni and the ΔkatA, Δcj1386, Δcj1386+cj1386^WT, and Δcj1386+cj1386^Y57A mutants. Strains were exposed to 10 μl of H₂O₂ and incubated under microaerophilic conditions at 37°C for 28 h, followed by measurement of the diameter of growth inhibition. Experiments were repeated in biological triplicate. Statistical significance was determined by ANOVA, with P < 0.05 considered significant.