Figure S1. (A) Peptide Sequence of SpaAcore. (B) MALDI-TOF MS analysis of SpaAcore peptide before and after incubation with SpaKC. (C) MSMS spectra of SpaKC-dehydrated SpaAcore peptide confirms that the dehydration occurs specifically at the Thr8 residue.

Figure S2. (A) Peptide Sequence of SpaA(4~13). (B) MALDI-TOF MS analysis of SpaA(4~13) peptide before and after incubation with SpaKC.

Figure S3. (A) Peptide Sequence of SpaA(7~13). (B) MALDI-TOF MS analysis of SpaA(7~13) peptide before and after incubation with SpaKC.

Figure S4. (A) Peptide Sequence of SpaA(7~13)T8S_C13A. (B) MALDI-TOF MS analysis of SpaA(7~13)T8S_C13A peptide before and after incubation with SpaKC.

Figure S5. (A) Peptide Sequence of SpaA(8~13). (B) MALDI-TOF MS analysis of SpaA(8~13) peptide before and after incubation with SpaKC.

Figure S6. (A) Peptide Sequence of SpaA(1~11). (B) MALDI-TOF MS analysis of SpaA(1~11) peptide before and after incubation with SpaKC.

Figure S7. (A) Peptide Sequence of SpaA(1~10). (B) MALDI-TOF MS analysis of SpaA(1~10) peptide before and after incubation with SpaKC.

Figure S8. (A) Peptide Sequence of SpaA(1~9). (B) MALDI-TOF MS analysis of SpaA(1~9) peptide before and after incubation with SpaKC.

Figure S9. (A) Peptide Sequence of SpaA(4~13)A5T_T8A. (B) MALDI-TOF MS analysis of SpaA(4~13)A5T_T8A peptide before and after incubation with SpaKC.

Figure S10. (A) Peptide Sequence of SpaA(4~13)A6T_T8A. (B) MALDI-TOF MS analysis of SpaA(4~13)A6T_T8A peptide before and after incubation with SpaKC.

Figure S11. (A) Peptide Sequence of SpaA(4~13)A7T_T8A. (B) MALDI-TOF MS analysis of SpaA(4~13)A7T_T8A peptide before and after incubation with SpaKC. [SpaA(4~13)A6T_T8A +H]+: Calc. mass 961.45 Da, Obs. mass 961.75 Da; [SpaA(4~13)A6T_T8A +Na]+: Calc. mass 983.44 Da, Obs. mass 983.74 Da.

Figure S12. (A) Peptide Sequence of SpaA(4~13)T8A_V9T. (B) MALDI-TOF MS analysis of SpaA(4~13)T8A_V9T peptide before and after incubation with SpaKC.

Figure S13. (A) Peptide Sequence of SpaA(4~13)T8A_A10T. (B) MALDI-TOF analysis of SpaA(4~13)T8A_A10T peptide before and after incubation with SpaKC.

Figure S14. (A) Peptide Sequence of SpaA(4~13)T8A_F11T. (B) MALDI-TOF analysis of SpaA(4~13)T8A_F11T peptide before and after incubation with SpaKC.