Fig. 2

Hypothetical conjugations of DAQs and DOPAL with protein residues, leading to protein modifications and cross-linking. a–c DAQ or DOPAL conjugations to peptide A. a SB adductive reaction of DOPAL with lysine; b MA adductive reaction of DOQ with cysteine; c MA adductive reaction of DOQ with tyrosine residue. d–i DAQ or DOPAL conjugation and cross-linking between peptides A and B. d MA adductive reactions of DOQ with two cysteine residues; e MA and SB adductive reactions of DPQ with cysteine and lysine residues, respectively; f MA adductive reactions of DOQ with tyrosine and cysteine residues; g MA adductive reactions of DOQ with two tyrosine residues; h MA and SB adductive reactions of DPQ with tyrosine and lysine residues, respectively; i MA and SB adductive reactions of DPQ with two lysine residues. j–o DAQ or DOPAL conjugations and cross-linking between peptides B and C. j MA adductive reactions of AM with two cysteine residues; k MA adductive reactions of AM with cysteine and tyrosine residues; l MA adductive reactions of AM with two tyrosine residues; m MA adductive reactions of DPQ with two cysteine residues; n MA adductive reactions of DPQ with cysteine and tyrosine residues; o MA adductive reactions of DPQ with two tyrosine residues; p–s Conjugations to peptide C. p MA adductive reaction of AM with cysteine residue; q MA adductive reaction of AM with tyrosine residue; r MA adductive reaction of DPQ with cysteine residue; s MA adductive reaction of DPQ with tyrosine residue