FIGURE 7.

Effect of residue and fragment swappings between FlaA and FlaB. A, to determine the residues accountable for functional difference of FlaA and FlaB, the relative swimming motility was calculated as the ratio of mutant flagellin (FlaA or FlaB) motility to wild type FlaB motility. A and B in normal type represent FlaA and FlaB, respectively. Letters and numbers in superscript represent amino acid residues and location, respectively. For example, A^T106S, A²⁷³⁻, and A^B99–186 represent FlaA harboring mutation T106S, removal of residue 273, and the fragment of residues 99–186 of FlaB, respectively. Double (residues 129 and 134) and Triple (residues 125, 129, and 134) represent multiple exchanges between two flagellins. Data are representative of at least three independent experiments with S.D. as the error bar. *, statistically significant difference (p < 0.01, n ≥ 3). B, conservation of residues that differ within FlaA and FlaB. Sequence conservation of Shewanella flagellins that are ∼270 amino acids in length was shown (residues 98–156). The actual residues in S. oneidensis FlaA (top) and FlaB (bottom) are given. The boxed residues dictated the functional difference. The sequence logo was produced with WebLogo.