Fig. 5. Mutually selective coiled-coils. (A) and (C), illustration of the location of individual lysine residues in PepK and ARS in PepE in the pairs of peptides (structure: pdb code 1u0i). (B) Scheme of the ligation reaction. (D) and (E), HPLC chromatograms (UV absorbance at 220 nm) of the products of the reaction of PepE(ARS8) with PepK(K13) (mismatch 1, D top) and PepK(K6) (match 1, D bottom), as well as of PepE(ARS15) with PepK(K6) (mismatch 2, E top) and PepK(K13) (match 2, E bottom). The shoulder in the product peak of match 2 corresponds to the peptide containing biotin sulfoxide. See Experimental section for details.